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  • 1.
    Boman, Mats
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Berger, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Corrosion of copper in water free from molecular oxygen2014In: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 49, no 6, p. 431-434Article in journal (Refereed)
    Abstract [en]

    The possibility of copper reacting with O-2-free water has been investigated by analysis of primary corrosion products, as well as by monitoring gas pressure change by time, in long term experiments for up to 6 months in a glove box environment. We establish hydrogen production, but being of the same magnitude irrespective whether copper is present or not. Although low, the hydrogen production rate is considerably larger than what would directly correspond to the amount of analysed copper oxidation products. Our analyses encompass the changes to the surface cleaned copper (99.9999%), the water phase and the Duran glass in contact with the water (ppt quality). We have used very sensitive methods (XPS, AES, ICP-MS, XRF) while keeping contamination risks to a minimum. We conclude that the oxidation rate of copper is very low, yielding only parts of a monolayer of Cu2O after 6 months of exposure at 50 degrees C together with an accompanying very low concentration of copper species (4-5 mu g L-1) in the water phase.

  • 2.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moro, Marcos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Hallén, Anders
    Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Luminescence of Silicon Nanoparticles from Oxygen Implanted Silicon2018In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 86, p. 18-22Article in journal (Refereed)
    Abstract [en]

    Oxygen with a kinetic energy of 20 keV is implanted in a silicon wafer (100) at different fluences, followed by post-implantation thermal annealing (PIA) performed at temperatures ranging from 1000 to 1200 degrees C, in order to form luminescent silicon nanoparticles (SiNPs) and also to reduce the damage induced by the implantation. As a result of this procedure, a surface SiOx layer (with 0 < x < 2) with embedded crystalline Si nanoparticles has been created. The samples yield similar luminescence in terms of peak wavelength, lifetime, and absorption as recorded from SiNPs obtained by the more conventional method of implanting silicon into silicon dioxide. The oxygen implantation profile is characterized by elastic recoil detection (ERD) technique to obtain the excess concentration of Si in a presumed SiO2 environment. The physical structure of the implanted Si wafer is examined by grazing incidence X-ray diffraction (GIXRD). Photoluminescence (PL) techniques, including PL spectroscopy, time-resolved PL (TRPL), and photoluminescence excitation (PLE) spectroscopy are carried out in order to identify the PL origin. The results show that luminescent SiNPs are formed in a Si sample implanted by oxygen with a fluence of 2 x 10(17) atoms cm(-2) and PIA at 1000 degrees C. These SiNPs have a broad size range of 6-24 nm, as evaluated from the GIXRD result. Samples implanted at a lower fluence and/or annealed at higher temperature show only weak defect-related PL. With further optimization of the SiNP luminescence, the method may offer a simple route for integration of luminescent Si in mainstream semiconductor fabrication.

  • 3.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Xie, Ling
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    LEIFER, KLAUS
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Ion Beam Synthesis of Luminescent Silicon NanoparticlesManuscript (preprint) (Other academic)
  • 4.
    Engelmark, Fredrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Fasta tillståndets elektronik.
    Iriarte, Gonzalo Fuentes
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Fasta tillståndets elektronik.
    Katardjiev, Ilia V
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Fasta tillståndets elektronik.
    Ottosson, M
    Department of Engineering Sciences, Electronics. Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Muralt, P
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Fasta tillståndets elektronik.
    Structural and electroacoustic studies of AIN thin films during low temperature radio frequency sputter deposition2001In: J Vac Sci Technol, Vol. A19, no 5, p. 2664-2669Article in journal (Refereed)
  • 5.
    Fallberg, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Phase stability and oxygen doping in the Cu-N-O system2010In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 312, no 10, p. 1779-1784Article in journal (Refereed)
    Abstract [en]

    A growth stability diagram for the system Cu-N-O has been determined in the temperature range 250-500°C for a thermally activated CVD process, based on copper (II) hexafluoroacetylacetonate (Cu(hfac)2), NH3 and H2O. Without any addition of water only Cu3N was obtained. Addition of water introduces oxygen into the Cu3N structure to a maximum amount of 9 atomic % at a water/nitrogen molar ratio of 0.36 at 325 °C. Above this molar ratio Cu2O starts to deposit in addition to an oxygen doped Cu3N phase. Only Cu2O is deposited at a large excess of water.

    XPS and Raman spectroscopy indicated that the additional oxygen in the doped Cu3N structure occupies an interstitial position with a chemical environment similar to oxygen in Cu2O. The oxygen doping of the Cu3N phase did not influence the lattice parameter which was close to the bulk parameter of 3.814 Å. The film morphology varied markedly with both deposition temperature and water concentration in the vapour during deposition.  Increasing the water concentration results in less faceted and textured films with smoother and more sphere like grains. The resistivity of the Cu3N films increased with increased oxygen content of the film and varied between 10-100 Ωcm (0 to 9 atomic% O). The optical band gap increased from 1.25 to 1.45 eV as the oxygen content increased (0 to 9 atomic %).

  • 6. Fallqvist, M.
    et al.
    Ruppi, S.
    Olsson, M.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grehk, T. M.
    Nucleation and growth of CVD alpha-Al2O3 on TixOy template2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 207, p. 254-261Article in journal (Refereed)
    Abstract [en]

    The microstructure, phase and chemical composition of TixOy, templates used to nucleate alpha-Al2O3 on Ti(C,N) coated cemented carbide have been elucidated using scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. Further, the adhesive strength of the alpha-Al2O3-TixOy-Ti(C,N) interfaces was investigated using scratch adhesion testing. The present study confirmed that the as-deposited template consisted of a Ti4O7 phase which during subsequent deposition of the Al2O3 layer transformed to a Ti3O5 phase and that the grown Al2O3 layer consisted of 100% alpha-Al2O3. Furthermore, the results showed that the lowest interfacial strength within the multilayer structure was exhibited by the Ti(C,N)-TixOy interface and that the transformation of Ti4O7 to Ti3O5 in the template resulted in formation of pores in the Ti(C,N)-template interface lowering the interfacial strength even more. The use of surface analysis techniques such as Auger electron spectroscopy and especially Time-of-Flight Secondary Ion Mass Spectrometry enabled trace element analyses using depth profiling to characterise the thin interfacial layers in detail. (c) 2012 Elsevier B.V. All rights reserved.

  • 7.
    Faris, A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Lööf, J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Hermansson, L
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    In vitro bioactivity of injectable ceramic orthopaedic cements2006In: Key Engineering Materials, Vol. 309-311, p. 833-836Article in journal (Refereed)
  • 8. Faris, Adam
    et al.
    Engqvist, HåkanUppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.Lööf, JesperOttosson, MikaelUppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.Hermansson, LeifUppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    In Vitro Bioactivity of Injectable Ceramic Orthopaedic Cements2006Conference proceedings (editor) (Refereed)
  • 9.
    Farkas, B.
    et al.
    Univ Szeged, Dept Opt & Quantum Elect, Szeged, Hungary; ELI HU Nonprofit Ltd, Szeged, Hungary.
    Heszler, P.
    Univ Szeged, Hungarian Acad Sci, Res Grp Laser Phys, Szeged, Hungary.
    Budai, J.
    Univ Szeged, Dept Opt & Quantum Elect, Szeged, Hungary.
    Oszko, A.
    Univ Szeged, Hungarian Acad Sci, React Kinet Res Grp, Szeged, Hungary.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Geretovszky, Zs.
    Univ Szeged, Dept Opt & Quantum Elect, Szeged, Hungary.
    Optical, compositional and structural properties of pulsed laser deposited nitrogen-doped Titanium-dioxide2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 433, p. 149-154Article in journal (Refereed)
    Abstract [en]

    N-doped TiO2 thin films were prepared using pulsed laser deposition by ablating metallic Ti target with pulses of 248 nm wavelength, at 330 °C substrate temperature in reactive atmospheres of N2/O2 gas mixtures. These films were characterized by spectroscopic ellipsometry, X-ray photoelectron spectroscopy and X-ray diffraction. Optical properties are presented as a function of the N2 content in the processing gas mixture and correlated to nitrogen incorporation into the deposited layers. The optical band gap values decreased with increasing N concentration in the films, while a monotonically increasing tendency and a maximum can be observed in case of extinction coefficient and refractive index, respectively. It is also shown that the amount of substitutional N can be increased up to 7.7 at.%, but the higher dopant concentration inhibits the crystallization of the samples.

  • 10.
    Hedin, Allan
    et al.
    SKB, Swedish Nucl Fuel & Waste Management Co, SE-10124 Stockholm, Sweden.
    Johansson, Adam Johannes
    SKB, Swedish Nucl Fuel & Waste Management Co, SE-10124 Stockholm, Sweden.
    Lilja, Christina
    SKB, Swedish Nucl Fuel & Waste Management Co, SE-10124 Stockholm, Sweden.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Berastegui, Pedro
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Berger, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Corrosion of copper in pure O2-free water?2018In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 137, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Copper exposed to pure, O-2-free water for several months in glass- and metal-contained, well-controlled systems shows no evidence of corrosion, either through hydrogen evolution or through the occurrence of oxidized copper. The results contradict the interpretation of recent experiments where it has been claimed that copper corrodes in pure, O-2-free water far above the very limited extent predicted by established thermodynamic data. Reasons for the different experimental outcomes are discussed. Experimental and theoretical efforts to identify hitherto unknown, potentially corrosion driving species of the Cu-O-H system and studies of copper/water surface reactions are reviewed as background for the present study.

  • 11. Intarasiri, Saweat
    et al.
    Yu, L.D.
    Singkarat, S.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Effects of low-fluence swift iodine ion bombardment on the crystallization of ion-beam-synthesized silicon carbide2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 8, p. 084311-Article in journal (Refereed)
    Abstract [en]

    Ion beam synthesis using high-fluence carbon ion implantation in silicon in combination with subsequent or in situ thermal annealing has been shown to be able to form nanocrystalline cubic SiC (3C-SiC) layers in silicon. In this study, a silicon carbide layer was synthesized by 40-keV C 12 + implantation of a p -type (100) Si wafer at a fluence of 6.5× 1017 ions cm2 at an elevated temperature. The existence of the implanted carbon in Si substrate was investigated by time-of-flight energy elastic recoil detection analysis. The SiC layer was subsequently irradiated by 10-30 MeV I 127 ions to a very low fluence of 1012 ions cm2 at temperatures from 80 to 800 °C to study the effect on the crystallization of the SiC layer. Infrared spectroscopy and Raman scattering measurement were used to monitor the formation of SiC and detailed information about the SiC film properties was obtained by analyzing the peak shape of the Si-C stretching mode absorption. The change in crystallinity of the synthesized layer was probed by glancing incidence x-ray diffraction measurement and transmission electron microscopy was also used to confirm the results and to model the crystallization process. The results from all these measurements showed in a coherent way that the synthesized structure was a polycrystalline layer with nanometer sized SiC crystals buried in a-Si matrix. The crystallinity of the SiC layer was enhanced by the low-fluence swift heavy ion bombardment and also favored by higher energy, higher fluence, and higher substrate temperature. It is suggested that electronic stopping plays a dominant role in the enhancement.

  • 12.
    Iriarte, Gonzalo Fuentes
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Engelmark, Fredrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. oorganisk kemi.
    Katardjiev, Ilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    The Influence of the Deposition Parameters on the Stress of Magnetron Sputter Deposited AlN Thin Films on Si (100) Substrates2003In: Journal of Materials Research, Vol. 18, no 2, p. 423-Article in journal (Refereed)
  • 13.
    Ivanov, Sergey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kumar Puri, Anil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bush, A. A.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Temperature evolution of structural and magnetic properties of stoichiometric LiCu2O2: Correlation of thermal expansion coefficient and magnetic order2014In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 34, p. 97-101Article in journal (Refereed)
    Abstract [en]

    Temperature-dependent crystallographic and magnetic studies on stoichiometric single crystals of LiCu2O2 are reported. The temperature dependence of the lattice parameters was extracted from X-ray powder diffractograms collected on crushed single crystals, from 12 K to 295 K. The magnetic properties are similar to earlier findings demonstrating antiferromagnetic ordering below 25 K. Evidence of magnetoelastic coupling is observed in the thermal expansion along the c-direction; not only at the low temperature antiferromagnetic transitions, but an anomalous behavior of the thermal expansion indicate magnetoelastic coupling also to the magnetic ordering related to a weak spontaneous magnetic moment appearing at 150 K. Ac-susceptibility measurements at different frequencies and superposed dc-fields are employed to further characterize this magnetic anomaly.

  • 14.
    Jacobsson, T. Jesper
    et al.
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, CH-1015 Lausanne, Switzerland..
    Schwan, L. Josef
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, CH-1015 Lausanne, Switzerland..
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Determination of Thermal Expansion Coefficients and Locating the Temperature-Induced Phase Transition in Methylammonium Lead Perovskites Using X-ray Diffraction2015In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 54, no 22, p. 10678-10685Article in journal (Refereed)
    Abstract [en]

    Lead halogen perovskites, and particularly methylammonium lead iodine, CH3NH3PbI3, have recently attracted considerable interest as alternative solar cell materials, and record solar cell efficiencies have now surpassed 20%. Concerns have, however, been raised about the thermal stability of methylammonium lead iodine, and a phase transformation from a tetragonal to a cubic phase has been reported at elevated temperature. Here, this phase transition has been investigated in detail using temperature-dependent X-ray diffraction measurements. The phase transformation is pinpointed to 54 degrees C, which is well within the normal operating range of a typical solar cell. The cell parameters were extracted as a function of the temperature, from which the thermal expansion coefficient was calculated. The latter was found to be rather high (alpha(v) = 1.57 X 10(-4) K-1) for both the tetragonal and cubic phases. This is 6 times higher than the thermal expansion coefficient for soda lime glass and CIGS and 11 times larger than that of CdTe. This could potentially be of importance for the mechanical stability of perovskite solar cells in the temperature cycling experienced under normal day night operation. The experimental knowledge of the thermal expansion coefficients and precise determination of the cell parameters can potentially also be valuable while conducting density functional theory simulations on these systems in order to deliver more accurate band structure calculations.

  • 15.
    Johansson, Anders
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Törndahl, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Boman, Mats
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Copper nanoparticles deposited inside the pores of anodized aluminium oxide using atomic layer deposition2003In: Materials Science and Engineering, Vol. C, no 23, p. 823-826Article in journal (Refereed)
  • 16. Kamentsev, K. E.
    et al.
    Bush, A. A.
    Tishchenko, E. A.
    Ivanov, Sergey A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ottoson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    High-temperature structural phase transition in the LiCu2O2 multiferroic2013In: Journal of Experimental and Theoretical Physics, ISSN 1063-7761, E-ISSN 1090-6509, Vol. 117, no 2, p. 320-326Article in journal (Refereed)
    Abstract [en]

    The results of thermogravimetric, X-ray diffraction, and electrical studies of LiCu2O2 single crystals in the temperature range 300-1100 K are presented. A reversible first-order phase transition between the orthorhombic and tetragonal phases is found to occur in these single crystals at T = 993 K. A pronounced peak on a differential thermal analysis curve and jumps in the unit cell parameters and the electrical resistivity are detected at the phase-transition temperature. The data on the crystal structure of LiCu2O2 and the phase transition-induced change in the entropy determined in this work are used to conclude that the revealed phase transition is caused by the ordering-disordering of Li+ and Cu2+ cations in their structural positions.

  • 17.
    Lagerqvist, Ulrika
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gunnarsson, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lu, Jun
    Hultman, Lars
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Pohl, Annika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Morphology effects on exchange anisotropy in Co-CoO nanocomposite films2015In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 576, p. 11-18Article in journal (Refereed)
    Abstract [en]

    Co-CoO composite films were prepared by solution chemical technique using amine-modified nitrates and acetates in methanol. We study how particle size and porosity can be tuned through the synthesis parameters and how this influences the magnetic properties. Phase content and microstructure were characterised with grazing incidence X-ray diffraction and electron microscopy, and the magnetic properties were studied by magnetometry and magnetic force microscopy. Composite films were obtained by heating spin-coated films in Ar followed by oxidation in air at room temperature, and the porosity and particle size of the films were controlled by gas flow and heating rate. The synthesis yielded dense films with a random distribution of metal and oxide nanoparticles, and layered films with porosity and sintered primary particles. Exchange anisotropy, revealed as a shift towards negative fields of the magnetic hysteresis curve, was found in all films. The films with a random distribution of metal and oxide nanoparticles displayed a significantly larger coercivity and exchange anisotropy field compared to the films with a layered structure, whereas the layered films displayed a larger nominal saturation magnetisation. The magnitude of the coercivity decreased with increasing Co grain size, whereas increased porosity caused an increased tilt of the magnetic hysteresis curve. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license

  • 18.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. AB Sandvik Coromant R&D, Lerkrogsvagen 19, SE-1280 Stockholm, Sweden..
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Doping of metastable Cu3N at different Ni concentrations: Growth, crystallographic sites and resistivity2018In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 647, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Copper nitride, Cu3N, is a metastable material whose properties can be changed considerably by doping with metals which opens for a variety of applications in several areas (sensors, electrical connects, batteries, memories, etc.). The present work is a systematic study in the system Cu-Ni-N of preferences regarding occupation of interstitial and substitutional crystallographic sites in the Cu3N structure as the metal dopant level increases and how the occupation influences growth behavior, texture, microstructure and resistivity. Ni doped Cu3N films of different chemical composition were grown by a gas-pulsed Chemical Vapor Deposition technique. The occupation of the different crystallographic sites of the Cu3N by the Ni atoms was obtained from analysis of X-ray diffraction data. At low Ni content, less than about 21% in metal content, Ni replaced the Cu atoms in the structure. In the intermediate Ni metal content range from about 21 to 40% the vacant centre position became available. After filling the centre position, substitution of Cu for Ni occurred up to a Ni content of about 80% (Cu0.8Ni3.2N) which is the solid solubility limit of Ni in Cu3N. The film resistivity decreased rapidly by adding nickel to the Cu3N structure from about 10(9)mu Omega.cm without any Ni doping to about 100 mu Omega.cm with 80% Ni in the metal content. After filling the centre position the change in resistivity when Cu atoms were substituted for Ni was very small. Finally, the growth mechanism, texture and microstructure changed significantly with the uptake of Ni atoms in the structure.

  • 19.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Gas-Pulsed CVD for Film Growth in the Cu-Ni-N System2012In: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 18, no 1-3, p. 10-16Article in journal (Refereed)
    Abstract [en]

    A new ternary solid solution, Cu3-xNix+yN, is prepared by gas-pulsed CVD at 260 degrees C. Gas pulses of the precursor mixtures Cu(hfac)2+NH3 and Ni(thd)2+NH3, separated by intermittent ammonia pulses, are employed for the deposition of Cu3N and Ni3N, respectively. A few monolayers of the nitrides are grown in each CVD pulse and then mixed by diffusion to produce the solid solution. The metal content of the solid solution can be varied continuously from 100% to about 20% Cu, which means that the electrical properties can be varied from 1.6eV (band gap of Cu3N) to metallic (Ni3N). This is of interest for various applications, e.g., solar energy, catalysis, and microelectronics.

  • 20.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Growth and stability of CVD Ni3N and ALD NiO dual layers2010In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 3, p. 710-716Article in journal (Refereed)
  • 21.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    In situ study of nickel formation during decomposition of chemical vapor deposition Ni3N films2010In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 28, no 5, p. 1203-1209Article in journal (Refereed)
    Abstract [en]

    The thermal decomposition of Ni3N thin films, deposited by chemical vapor deposition on SrTiO3 (001) and Si (100) substrates, has been studied by in situ x-ray diffraction, as well as temperature-programed controlled gas emission in both inert and hydrogen atmospheres. The decomposition at inert atmosphere conditions starts at the film/substrate interface, which results in a high degree of ordering in the formed nickel film. In the H-2 atmosphere, the initial film ordering is less pronounced and the decomposition occurs from the film surface and downward. This means that by choosing the annealing atmosphere, inert or hydrogen, the formation of the Ni film can be localized to either the original nitride/substrate interface or to the surface of the nitride. The annealed films show a cube-on-cube growth with respect to the SrTiO3 (001) substrate. The film morphology after the annealing experiments resembles the one of the as-deposited films. The lowest resistivity value is measured for the films annealed in the H-2 atmosphere. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3478298]

  • 22.
    Lu, J
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Sundqvist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Tarre, A
    Rosental, A
    Aarik, J
    Hårsta, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Microstructure characterisation of ALD-grown epitaxial SnO2 thin films2004In: Journal of Crystal Growth, no 260, p. 191-200Article in journal (Refereed)
  • 23.
    Mao, Fang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Taher, Mamoun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Kryshtal, Oleksandr
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Kruk, Adam
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Czyrska-Filemonowicz, Aleksandra
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Anna M.
    ABB AB, Corp Res, SE-72178 Vasteras, Sweden..
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Combinatorial Study of Gradient Ag-Al Thin Films: Microstructure, Phase Formation, Mechanical and Electrical Properties2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 44, p. 30635-30643Article in journal (Refereed)
    Abstract [en]

    A combinatorial approach is applied to rapidly deposit and screen Ag-Al thin films-to evaluate the mechanical, tribological, and electrical properties as a function of chemical composition. Ag-Al thin films with large continuous composition gradients (6-60 atom % Al) were deposited by a custom-designed combinatorial magnetron sputtering system. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and four-point electrical resistance screening were employed to characterize the chemical composition, structure, and physical properties of the films in a time-efficient way. For low Al contents (<13 atom %), a highly (111)-textured fcc phase was formed. At higher Al contents, a (002)-textured hcp solid solution phase was formed followed by a fcc phase in the most At-rich regions. No indication of a mu phase was observed. The Ag-Al films with fcc-Ag matrix is prone to adhesive material transfer leading to a high friction coefficient (>1) and adhesive wear, similar to the behavior of pure Ag. In contrast, the hexagonal solid solution phase (from ca. 15 atom %Al) exhibited dramatically reduced friction coefficients (about 15% of that of the fcc phase) and dramatically reduced adhesive wear when tested against the pure Ag counter surface. The increase in contact resistance of the Ag Al films is limited to only 50% higher than a pure Ag reference sample at the low friction and low wear region (19-27 atom %). This suggests that a hcp Ag Al alloy can have a potential use in sliding electrical contact applications and in the future will replace pure Ag in specific electromechanical applications.

  • 24.
    Mårlid, Björn
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Pettersson, U
    Technology, Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Larsson, Karin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Atomic layer deposition of BN thin films2002In: Thin Solid Films, no 402, p. 167-171Article in journal (Refereed)
  • 25.
    Olander, Jenny
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Heszler, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Larsson, Karin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Laser-Assisted Atomic Layer Deposition of Boron Nitride Thin Films2005In: Chemical Vapor Deposition, Vol. 11, p. 330-337Article in journal (Refereed)
    Abstract [en]

    Boron nitride thin films have been grown by both laser-assisted, and conventional atomic layer deposition (LALD/ALD) at temperatures in the range 250-750 °C. Both the NH3 and BBr3 precursors were appreciably dissociated by the ArF excimer laser, and up to 600 °C, the growth rate was 100 % higher for the LALD process than for ALD. The films consisted of hydrogen-terminated turbostratic BN grains. H2 was theoretically found to bind as strongly as BBrX and NHX (X = 0-2) to hBN(100) edges. The fresh films were stoichiometric with respect to B and N, and contained low degrees of contamination, but oxidized easily in air.

  • 26.
    Ottosson, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Berastegui, Pedro
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Korvela, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Berger, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Response to the comments by P. Szakalos, T. angstrom kermark and C. Leygraf on the paper "Copper in ultrapure water, a scientific issue under debate"2018In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 142, p. 308-311Article in journal (Other academic)
  • 27.
    Ottosson, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Berastegui, Pedro
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Hedlund, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Korvela, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Berger, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Copper in ultrapure water, a scientific issue under debate2017In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 122, p. 53-60Article in journal (Refereed)
    Abstract [en]

    The corrosion properties of copper in ultrapure water have been studied experimentally by submerging copper samples (99.9999%) in pure water for up to 29 months. The surface was first electropolished at ambient temperature, then exposed to hydrogen gas treatment at 300-400 degrees C, thereby reducing the bulk hydrogen content to 0.03 ppm. These copper samples, the water and the glassware were all then subjected to precise chemical analysis. Great care was taken to avoid contamination. After exposure, only similar to 6 mu g/L copper had accumulated in the water phase. Electron spectroscopy could not detect Cu2O or any other oxidation products containing copper.

  • 28.
    Ottosson, Mikael
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Törndahl, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    In-situ quartz crystal microbalance investigation of atomic layer deposition of Cu3N2005In: Electrochemical Society v. PV 2005-09 EUROCVD-15: Fifteenth European Conference on Chemical Vapor Deposition, 2005, p. 591-597Conference paper (Refereed)
  • 29.
    Pohl, Annika
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Lashgari, K
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    La0.5Sr0.5CoO3 electrode films by alkoxide based sol-gel synthesis2005In: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005, p. 2-Conference paper (Refereed)
  • 30.
    Pohl, Annika
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Porous and dense perovskite films2007In: Nanostructured Materials and Nanotechnology, Vol 28, 2007, p. 153-163Conference paper (Refereed)
    Abstract [en]

    Lao.5Sro.5Co03 (LSCO) and La0.67Ca0.33MnO3 (LCMO) films were prepared by sol-gel techniques and their structural and transport properties investigated. Films were spin-coated onto (001) LaAlO3 (LAO), (001) SrTiO3 (STO), Pt/TiO2/SiO2/Si, and Al2O3 substrates, and ictural properties were investigated using X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM). SEM studies showed that the films were crack-free and adhered well to the substrates. No preferential orientation of the pervoskite films was observed on Si- or Pt/TiCVSiCVSi-substrates, but films deposited on LAO and STO showed good alignment with the substrate. Transport measurements of epitaxial LCMO films show maximum temperature coefficient of resisth (TCR) of 6.1 % K1 aät 241 K and colossal magnetoresistance (CMR) of 32 % a at 246 K. The conductivity of around l .9 mQcm.

  • 31. Rosental, Arnold
    et al.
    Tarre, Aivar
    Gerst, Alar
    Kasikov, Aarne
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Uustare, Teet
    Epitaxial Single and Double Nanolayers of SnO2 and TiO2 for Resistive Gas Sensors2013In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 13, no 5, p. 1648-1655Article in journal (Refereed)
    Abstract [en]

    Rutile TiO2 (1 0 1) and cassiterite SnO2 (1 0 1) epitaxial single and double nanolayers, the latter stacked in either sequence, are atomic layer deposited on r-cut alpha-Al2O3(0 1 (1) over bar 2) substrates. Thickness of the layers is varied. Epitaxial quality of the films is characterized by X-ray diffraction (XRD), reflection high-energy electron diffraction, and transmission electron microscopy. In gas response measurements, as-grown films and the films coated with electron-beam evaporated Pt nanoclusters are exposed, at 350 degrees C, to H-2, CO, and CH4 diluted in air. In response to test gas concentrations of 30 parts per million (ppm), the films with a thickness of order of 10 nm exhibit, depending on the makeup and gas, as high as two- to five-fold decrease in the resistance. It is shown that the platinum surface catalyst is effective in accelerating the response and recovery processes. The transition times of the order of a few tens of seconds are observed. The results demonstrate the feasibility of gas sensing with single-crystal-like nanolayer films. Comparison of sensor characteristics of such quasi-2D nanostructures and the literature data relevant to individual nanowires, nanorods, and nanobelts, i.e., typical representatives of the quasi-1D structures, shows that, as to H-2, CO, and CH4, both structures are worthy competitors.

  • 32. Sundqvist, Jonas
    et al.
    Lu, Jun
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Hårsta, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Growth of SnO2 thin films by atomic layer deposition and chemical vapour deposition: A comparative study2006In: Thin Solids Films, Vol. 514, no 1-2, p. 63-68Article in journal (Refereed)
    Abstract [en]

    Thin films of the tetragonal rutile-type SnO2 phase have been deposited by both atomic layer deposition (ALD) and chemical vapour deposition (CVD) using the SnI4–O2 precursor combination. Depositions were carried out in the temperature region of 350–750 °C on α-Al2O3(0 1 2) substrates. In both cases the films were found to grow epitaxially with the in-plane orientation relationships [0 1 0]SnO2 || [1 0 0]α-Al2O3 and [1 0 1¯]SnO2 || [1¯ 2¯ 1]α-Al2O3. Films grown by ALD were found to be close to perfectly single crystalline, contained a low density of defects and were almost atomically smooth. The CVD films were found to have a much rougher film morphology, and exhibited both grain boundaries and twin formation.

  • 33.
    Sundqvist, Jonas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Hårsta, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    CVD of Epitaxal SnO2 Films by SnL4/O2 Precursor Combination2004In: Chem. Vap. Deposition, Vol. 10, no 2, p. 77-82Article in journal (Refereed)
  • 34.
    Törndahl, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Lu, Jun
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Epitaxy of copper on α-Al2O3(0 0 1) by atomic layer deposition2005In: Journal of Crystal Growth, Vol. 276, p. 102-110Article in journal (Refereed)
    Abstract [en]

    A combined X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) study have been carried out on copper films grown by atomic layer deposition at 400 °C. The copper films have been grown on single crystalline (0 0 1) oriented α-Al2O3 up to a thickness of 500 nm. The films were relaxed and the diffraction peak broadening in 2θ was mainly dependent on the copper grain size. Broadening of the diffraction peaks in ω was found to be related to defects (mosaicity and intrinsic microstrain). The deposited films were epitaxial and grew with the (1 1 1) plane in parallel to the substrate surface. Extensive twinning in the copper grains in different Cu1 1 1 directions occurred according to the TEM study, both in directions perpendicular to the substrate surface ([1 1 1] and ) and along other 1 1 1 directions as well. As an effect of a twin, an extra Cu(5 1 1) orientation was present in the XRD data.

  • 35.
    Törndahl, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Growth of copper metal by atomic layer deposition using copper(I) chloride, water and hydrogen as precursors2004In: Thin Solid Films, no 458, p. 129-136Article in journal (Refereed)
  • 36.
    Törndahl, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Growth of Copper(I) Nitride by ALD Using Copper(II) Hexafluoroacetylacetonate, Water and Ammonia as Precursors2006In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 153, no 3, p. C146-C151Article in journal (Other academic)
    Abstract [en]

    Films of copper(I) nitride were deposited by atomic layer deposition (ALD) using copper(II) hexafluoroacetylacetonate, water, and ammonia as precursors. Introduction of a water pulse in the ALD cycle was found to be crucial for initiating film growth on both amorphous SiO2 and single-crystalline α-Al2O3(001) substrates. The water pulses generated an oxidic copper monolayer, which in a subsequent ammonia pulse was converted to the nitride. The films have been grown in the temperature range from 210to302°C . Phase pure films of Cu3N were obtained up to 265°C . At higher deposition temperatures such as 283°C , phase mixtures of Cu3N and Cu were obtained. For temperatures above 302°C films of only Cu were grown. Film growth rate was the same on the two different substrates. The films were randomly oriented on SiO2 . Completely intact films were obtained at a thickness of 20nm . The optical bandgap of the films was measured to be 1.6eV .

  • 37.
    Westin, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Pohl, Annika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Alkoxide route to La0.5Sr0.5CoO3 epitaxial thin films on SrTiO32008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 516, no 15, p. 4673-4678Article in journal (Refereed)
    Abstract [en]

    An all alkoxide based sol–gel route was investigated for preparation of epitaxial La0.5Sr0.5CoO3 (LSCO) films on 100 SrTiO3 (STO) substrates. Films with 20–30 to 80–100 nm thickness were prepared by spin-coating 0.2–0.6 M (metal) solutions on the STO substrates and heat treatment to 800 °C at 2 °C min− 1, 30 min, in air. The films were epitaxial with a cube-on-cube alignment and the LSCO cell was strained to match the STO substrate of 3.905 Å closely; a and b = 3.894 Å and 3.897 Å for the 20–30 and 80–100 nm films, respectively. The c-axis was compressed to 3.789 Å and 3.782 Å for the 20–30 and 80–100 nm films, respectively, which resulted in an almost unchanged cell volume as compared to polycrystalline film and nano-phase powders prepared in the same way. The SEM study showed mainly very smooth, featureless surfaces, but also some defects. A film prepared in the same way on an -Al2O3 substrate was dense and polycrystalline with crystallite sizes in the range 10–50 nm and gave cubic cell dimensions of ac = 3.825 Å. The conductivity of the ca 30–40 nm thick polycrystalline film was 1.7 mΩcm, while the epitaxial 80–100 nm film had a conductivity of around 1.9 mΩcm.

  • 38.
    Westin, Gunnar
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Pohl, Annika
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ottosson, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, K
    Direct processing of porous nano-structured ZnO:Co films2005In: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005Conference paper (Refereed)
  • 39.
    Westin, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Pohl, Annika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Jansson, Kjell
    Direct processing of porous nano-structured ZnO-CoOx films2007In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 20-21, p. 7751-7757Article in journal (Refereed)
    Abstract [en]

    Highly porous nano-structured films and powders of ZnO:Co (0–5 metal% Co) or ZnO:Co and (Zn,Co)3O4 (10–35% Co) particles were obtained by deposition of mixed Zn- and Co-methoxy-ethoxide precursors on spinning or non-spinning substrates, and heating to 600 °C. The Co- and Zn-methoxy-ethoxide solutions were prepared by metathesis of CoCl2 and potassium methoxy-ethoxide, and reaction of diethylzinc and methoxy-ethanol, respectively. Compositions in the range 0–35% Co were investigated by IR spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray diffraction. The gels obtained consisted of hydrated amorphous oxo-carbonates and were of good elemental homogeneity in the TEM. Thermogravimetric analysis showed that all residual groups had been removed at 550–600 °C, 5 °C min− 1. The materials heated to 600 °C contained ZnO of the hexagonal modification with cell-edges in close agreement with un-doped ZnO regardless of composition and temperature. TEM-EDS studies showed that the ZnO:Co and (Zn,Co)3O4 spinel particles were well mixed, of similar shape and size, ca 10–25 nm. Heating of the 10% Co sample to 800 °C decomposed the spinel phase and left Co-doped ZnO.

  • 40.
    Wikberg, J. M.
    et al.
    Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 AJ Nijmegen, Netherlands..
    Razdolski, I.
    Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 AJ Nijmegen, Netherlands..
    Kirilyuk, A.
    Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 AJ Nijmegen, Netherlands..
    Rasing, Th.
    Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 AJ Nijmegen, Netherlands..
    Sadowski, J.
    Lund Univ, MAX Lab, SE-22100 Lund, Sweden..
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Wei, Y.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Evolving magnetization dynamics in Mn3-xGa2015In: Ultrafast Magnetism I / [ed] Bigot, JY; Hubner, W; Rasing, T; Chantrell, R, 2015, p. 23-25Conference paper (Refereed)
  • 41.
    Wikberg, J Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Audren, A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Linnarsson, M K
    Royal Institute of Technology, KTH-ICT, Electrum, Stockholm.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Hallén, A
    Royal Institute of Technology, KTH-ICT, Electrum, Stockholm.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Annealing effects on structural and magnetic properties of Co implanted ZnO single crystals2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 8, p. 083918-Article in journal (Refereed)
    Abstract [en]

    Single crystals of ZnO were implanted with 100 keV-Co ions at room temperature with a fluence of 4.8 x 10(16) cm(-2) and subsequently annealed at different temperatures up to 800 degrees C. The samples were analyzed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, X-ray photoemission spectroscopy and magnetometry. The as-implanted Co:ZnO crystal shows a homogeneous distribution of Co in the near surface region of the crystal. Upon annealing, clear evidence of secondary phases is found. At the highest annealing temperature (800 degrees C) a ferromagnetic behavior is observed at room temperature with a coercive field of 120 Oe assigned mainly to metallic fcc Co nano-crystallites. We find that for the annealed samples, the temperature dependent magnetization cannot be explained within a model containing only a paramagnetic contribution due to well dispersed Co ions and a ferromagnetic contribution due to Co nano-crystallites, at least one more ferromagnetic contribution is needed for a consistent explanation of the experimental results.

  • 42.
    Wikberg, J Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Bhandary, Sumanta
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Di Marco, Igor
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sadowski, Janusz
    MAX-lab, Lund University.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Palmgren, Pål
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Tai, Cheuk W
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Magnetocrystalline anisotropy and uniaxiality of MnAs/GaAs(100) films2011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 2, p. 024417-Article in journal (Refereed)
    Abstract [en]

    We present an investigation of the magnetic behavior of epitaxial MnAs films grown on GaAs(100). We address the dependence of the magnetic moment, ferromagnetic transition temperature (Tc), and magnetocrystalline anisotropy constants on epitaxial conditions. From thorough structural and magnetic investigations, our findings indicate a more complex relationship between strain and magnetic properties in MnAs films than a simple stretch/compression of the unit cell axes. While a small increase is seen in the anisotropy constants, the enhancement of the magnetic moment at saturation is significant. Results of x-ray magnetic circular dichroism show a behavior of the spin and orbital moment that is consistent with a structural transition at Tc. In particular, we find that the ratio of the orbital to the spin moment shows a marked increase in the coexistence region of the ferromagnetic α- and paramagnetic β-phases a result that is well in accord with the observed increase in the c/a ratio in the same temperature region. The ab initio density functional calculations reveal that the magnetic properties are more sensitive towards change in the ab-plane compared to change in the c-axis which is explained by the analysis of band structures. The effects of electron correlation in MnAs using ab initio dynamical mean field theory are also presented.

1 - 42 of 42
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