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Primetzhofer, DanielORCID iD iconorcid.org/0000-0002-5815-3742
Publications (10 of 109) Show all publications
Bruckner, B., Bauer, P. & Primetzhofer, D. (2020). Neutralization of slow helium ions scattered from single crystalline aluminum and tantalum surfaces and their oxides. Surface Science, 691, Article ID 121491.
Open this publication in new window or tab >>Neutralization of slow helium ions scattered from single crystalline aluminum and tantalum surfaces and their oxides
2020 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 691, article id 121491Article in journal (Refereed) Published
Abstract [en]

We investigated the impact of surface oxygen on the ion yield for He+ ions scattered from different single crystalline surfaces in low-energy ion scattering. Initially clean Al(111) and Ta(111) were exposed to molecular oxygen and ion spectra for different oxidation stages and different primary energies were recorded. A comparison of ion yields normalized to the differential scattering cross section as well as experimental factors allows obtaining information about the influence of oxygen on charge exchange processes. The decrease in the ion yield of both metals with exposure cannot be explained by different surface coverages exclusively, but requires the neutralization efficiency to be dependent on the chemical structure of the surface. For Ta, additionally, a different energy dependency of the ion yield obtained in the metal and oxide occurs. The ion yield for O shows in both surfaces a significantly weaker energy dependency than the investigated metals.

Keywords
Low energy ion scattering, Ion yields, Charge exchange, Oxygen exposure, Al(111), Ta(111)
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-394735 (URN)10.1016/j.susc.2019.121491 (DOI)
Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-10-28Bibliographically approved
Huang, K., Wu, L., Wang, M., Swain, N., Motapothula, M., Luo, Y., . . . Renshaw Wang, X. (2020). Tailoring magnetic order via atomically stacking 3d/5d electrons to achieve high-performance spintronic devices. APPLIED PHYSICS REVIEWS, 7(1), Article ID 011401.
Open this publication in new window or tab >>Tailoring magnetic order via atomically stacking 3d/5d electrons to achieve high-performance spintronic devices
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2020 (English)In: APPLIED PHYSICS REVIEWS, ISSN 1931-9401, Vol. 7, no 1, article id 011401Article, review/survey (Refereed) Published
Abstract [en]

The ability to tune magnetic orders, such as magnetic anisotropy and topological spin texture, is desired to achieve high-performance spintronic devices. A recent strategy has been to employ interfacial engineering techniques, such as the introduction of spin-correlated interfacial coupling, to tailor magnetic orders and achieve novel magnetic properties. We chose a unique polar-nonpolar LaMnO3/SrIrO3 superlattice because Mn (3d)/Ir (5d) oxides exhibit rich magnetic behaviors and strong spin-orbit coupling through the entanglement of their 3d and 5d electrons. Through magnetization and magnetotransport measurements, we found that the magnetic order is interface-dominated as the superlattice period is decreased. We were able to then effectively modify the magnetization, tilt of the ferromagnetic easy axis, and symmetry transition of the anisotropic magnetoresistance of the LaMnO3/SrIrO3 superlattice by introducing additional Mn (3d) and Ir (5d) interfaces. Further investigations using in-depth first-principles calculations and numerical simulations revealed that these magnetic behaviors could be understood by the 3d/5d electron correlation and Rashba spin-orbit coupling. The results reported here demonstrate a new route to synchronously engineer magnetic properties through the atomic stacking of different electrons, which would contribute to future applications in high-capacity storage devices and advanced computing.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2020
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-403039 (URN)10.1063/1.5124373 (DOI)000505723100001 ()
Funder
Australian Research Council, FT160100207
Note

De två första författarna delar förstaförfattarskapet.

Available from: 2020-01-23 Created: 2020-01-23 Last updated: 2020-01-23Bibliographically approved
Warnatz, T., Skovdal, B. E., Magnus, F., Stopfel, H., Primetzhofer, D., Stein, A., . . . Hjörvarsson, B. (2020). The influence of diameter on the magnetic saturation in Fe 84 Cu 16 /MgO [001] multilayered islands. Journal of Magnetism and Magnetic Materials, 496, Article ID 165864.
Open this publication in new window or tab >>The influence of diameter on the magnetic saturation in Fe 84 Cu 16 /MgO [001] multilayered islands
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2020 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 496, article id 165864Article in journal (Refereed) Published
Abstract [en]

The saturation field of circular islands, consisting of [Fe84Cu16/MgO]9Fe84Cu16 multilayers, increases with decreasing diameter of the islands. When the diameter of the islands is below 450 nm the field induced changes are dominated by a coherent rotation of the moment of the Fe84Cu16 layers. For diameters of 2 μm and larger, a signature of domain nucleation and evolution is observed. The changes in the saturation field with diameter of the islands are ascribed to the interplay between interlayer exchange coupling, stray field coupling at the edges and the crystalline anisotropy of the Fe84Cu16 layers.

Keywords
finite size, patterning, interlayer exchange, coupling, magnetic multilayer
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-394276 (URN)10.1016/j.jmmm.2019.165864 (DOI)000491941800003 ()
Funder
Swedish Research Council, 821-2012-5144Swedish Foundation for Strategic Research , RIF14-0053Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-11-15Bibliographically approved
Garcia, J., Andersson Sundén, E., Binda, F., Cecconello, M., Conroy, S., Ericsson, G., . . . Zychor, I. (2019). A new mechanism for increasing density peaking in tokamaks: improvement of the inward particle pinch with edge E x B shearing. Plasma Physics and Controlled Fusion, 61(10), Article ID 104002.
Open this publication in new window or tab >>A new mechanism for increasing density peaking in tokamaks: improvement of the inward particle pinch with edge E x B shearing
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2019 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 61, no 10, article id 104002Article in journal (Refereed) Published
Abstract [en]

Developing successful tokamak operation scenarios, as well as confident extrapolation of present-day knowledge requires a rigorous understanding of plasma turbulence, which largely determines the quality of the confinement. In particular, accurate particle transport predictions are essential due to the strong dependence of fusion power or bootstrap current on the particle density details. Here, gyrokinetic turbulence simulations are performed with physics inputs taken from a JET power scan, for which a relatively weak degradation of energy confinement and a significant density peaking is obtained with increasing input power. This way physics parameters that lead to such increase in the density peaking shall be elucidated. While well-known candidates, such as the collisionality, previously found in other studies are also recovered in this study, it is furthermore found that edge E x B shearing may adopt a crucial role by enhancing the inward pinch. These results may indicate that a plasma with rotational shear could develop a stronger density peaking as compared to a non-rotating one, because its inward convection is increased compared to the outward diffusive particle flux as long as this rotation has a significant on E x B flow shear stabilization. The possibly significant implications for future devices, which will exhibit much less torque compared to present day experiments, are discussed.

Keywords
turbulence, transport, plasma
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-399008 (URN)10.1088/1361-6587/ab31a4 (DOI)000482602800002 ()
Note

For complete list of authors see http://dx.doi.org/10.1088/1361-6587/ab31a4

Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2019-12-13Bibliographically approved
Moro, M. V., Holeňák, R., Medina, L. Z., Jansson, U. & Primetzhofer, D. (2019). Accurate high-resolution depth profiling of magnetron sputtered transition metal alloy films containing light species: A multi-method approach. Thin Solid Films, 686, Article ID 137416.
Open this publication in new window or tab >>Accurate high-resolution depth profiling of magnetron sputtered transition metal alloy films containing light species: A multi-method approach
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2019 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 686, article id 137416Article in journal (Refereed) Published
Abstract [en]

We present an assessment of a multi-method approach based on ion beam analysis to obtain high-resolution depth profiles of the total chemical composition of complex alloy systems. As a model system we employ an alloy based on several transition metals and containing light species. Samples have been investigated by a number of different ion-beam based techniques, i.e., Rutherford Backscattering Spectrometry, Particle-Induced X-ray Emission, Elastic Backscattering Spectrometry and Time-of-Flight/Energy Elastic Recoil Detection Analysis. Sets of spectra obtained from these different techniques were analyzed both independently and following an iterative and self-consistent approach yielding a more accurate depth profile of the sample, including both metallic heavy constituents (Cr, Fe and Ni) as well as the rather reactive light species (C, O) in the alloy. A quantitative comparison in terms of achievable precision and accuracy is made and the limitations of the single method approach are discussed for the different techniques. The multi-method approach is shown to yield significantly improved and accurate information on stoichiometry, depth distribution and thickness of the alloy with the improvements being decisive for a detailed correlation of composition to the material properties such as corrosion strength. The study also shows the increased relative importance of experimental statistics for the achievable accuracy in the multi-method approach.

Keywords
High-resolution, Composition depth profiling, Ion beam analysis, Metal alloys, Magnetron sputtered thin-films
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-390959 (URN)10.1016/j.tsf.2019.137416 (DOI)000480474400001 ()
Funder
Swedish Research Council, 821-2012-5144Swedish Research Council, 2017-00646_9Swedish Research Council, 2018-04834Swedish Foundation for Strategic Research , RIF14-0053Vinnova, 2016-05156Carl Tryggers foundation
Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-09-30Bibliographically approved
Murari, A., Andersson Sundén, E., Binda, F., Cecconello, M., Conroy, S., Ericsson, G., . . . Zychor, I. (2019). Adaptive learning for disruption prediction in non-stationary conditions. Nuclear Fusion, 59(8), Article ID 086037.
Open this publication in new window or tab >>Adaptive learning for disruption prediction in non-stationary conditions
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2019 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 59, no 8, article id 086037Article in journal (Refereed) Published
Abstract [en]

For many years, machine learning tools have proved to be very powerful disruption predictors in tokamaks. On the other hand, the vast majority of the techniques deployed assume that the input data is independent and is sampled from exactly the same probability distribution for the training set, the test set and the final real time deployment. This hypothesis is certainly not verified in practice, since the experimental programmes evolve quite rapidly, resulting typically in ageing of the predictors and consequent suboptimal performance. This paper describes various adaptive training strategies that have been tested to maintain the performance of disruption predictors in non-stationary conditions. The proposed approaches have been implemented using new ensembles of classifiers, explicitly developed for the present application. The improvements in performance are unquestionable and, given the difficulties encountered so far in translating predictors from one device to another, the proposed adaptive methods from scratch can therefore be considered a useful option in the arsenal of alternatives envisaged for the next generation of devices, particularly at the very beginning of their operation.

Keywords
disruptions, machine learning predictors, adaptive training, de-learning, obsolescence, ensembles of classifiers
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-398830 (URN)10.1088/1741-4326/ab1ecc (DOI)000474298800006 ()
Note

For complete list of authors see http://dx.doi.org/10.1088/1741-4326/ab1ecc

Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2019-12-13Bibliographically approved
Gründlinger, P., Györök, M., Wolfmayr, S., Breuer, T., Primetzhofer, D., Bruckner, B., . . . Wagner, T. (2019). Aggregation of Au(i)-complexes on amorphous substrates governed by aurophilicity. Dalton Transactions, 48(39), 14712-14723
Open this publication in new window or tab >>Aggregation of Au(i)-complexes on amorphous substrates governed by aurophilicity
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2019 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 39, p. 14712-14723Article in journal (Refereed) Published
Abstract [en]

In single crystals of 2-naphthylisonitrile-gold(i)-halide (halide = Cl, Br, I) complexes, AuMIDLINE HORIZONTAL ELLIPSISAu distances are found to be significantly shorter than twice the van der Waals radius, indicating attractive interactions between gold atoms in adjacent molecules. In the particular case of the studied 2-naphthylisonitrile-gold(i) complexes, homodimers are the common structural motifs, in which the linearly coordinated gold exhibits a crossed swords arrangement with the Au atoms of two molecules being at the intersection point. The crossed swords motif is preserved upon physical vapour deposition of both the chlorine and bromine derivatives on amorphous substrates like glass and glassy carbon. The determined activation energies of desorption for the chlorine (0.9 eV) and the bromine (1.2 eV) derivative are comparable to that of unsubstituted naphthalene. Using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ion scattering (RBS), we confirmed the chemical integrity of the molecules in thin films and revealed the orientation of the crossed swords dimers with respect to the substrate surface.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-396704 (URN)10.1039/c9dt03049b (DOI)000489155800017 ()31539005 (PubMedID)
Funder
Swedish Research Council, 821-2012-5144Swedish Foundation for Strategic Research , RIF14-0053
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Englund, S., Kubart, T., Keller, J., Moro, M. V., Primetzhofer, D., Suvanam, S. S., . . . Platzer Björkman, C. (2019). Antimony-Doped Tin Oxide as Transparent Back Contact in Cu2ZnSnS4 Thin-Film Solar Cells. Physica Status Solidi (a) applications and materials science, 216(22), Article ID 1900542.
Open this publication in new window or tab >>Antimony-Doped Tin Oxide as Transparent Back Contact in Cu2ZnSnS4 Thin-Film Solar Cells
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2019 (English)In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 216, no 22, article id 1900542Article in journal (Refereed) Published
Abstract [en]

Antimony-doped tin oxide (Sn2O3:Sb, ATO) is investigated as a transparent back contact for Cu2ZnSnS4 (CZTS) thin-film solar cells. The stability of the ATO under different anneal conditions and the effect from ATO on CZTS absorber growth are studied. It is found that ATO directly exposed to sulfurizing anneal atmosphere reacts with S, but when covered by CZTS, it does not deteriorate when annealed at T < 550 degrees C. The electrical properties of ATO are even found to improve when CZTS is annealed at T = 534 degrees C. At T = 580 degrees C, it is found that ATO reacts with S and degrades. Analysis shows repeatedly that ATO affects the absorber growth as large amounts of Sn-S secondary compounds are found on the absorber surfaces. Time-resolved anneal series show that these compounds form early during anneal and evaporate with time to leave pinholes behind. Device performance can be improved by addition of Na prior to annealing. The best CZTS device on ATO back contact herein has an efficiency of 2.6%. As compared with a reference on a Mo back contact, a similar open-circuit voltage and short-circuit current density are achieved, but a lower fill factor is measured.

Keywords
antimony-doped tin oxides, Cu2ZnSnS4, sulfurization, thin-film solar cells, transparent back contacts
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-402260 (URN)10.1002/pssa.201900542 (DOI)000488074100001 ()
Funder
Swedish Foundation for Strategic Research , FFL13-0178Swedish Foundation for Strategic Research , RMA15‐0030Swedish Foundation for Strategic Research , RIF13‐0053Swedish Research Council, 821‐2012‐5144Swedish Research Council, 2017‐00646 9
Available from: 2020-01-13 Created: 2020-01-13 Last updated: 2020-01-31Bibliographically approved
Larsson, F., Keller, J., Primetzhofer, D., Riekehr, L., Edoff, M. & Törndahl, T. (2019). Atomic layer deposition of amorphous tin-gallium oxide films. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 37(3), Article ID 030906.
Open this publication in new window or tab >>Atomic layer deposition of amorphous tin-gallium oxide films
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2019 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 3, article id 030906Article in journal (Refereed) Published
Abstract [en]

A wide range of applications benefit from transparent semiconducting oxides with tunable electronic properties, for example, electron transport layers in solar cell devices, where the electron affinity is a key parameter. Presently, a few different ternary oxides are used for this purpose, but the attainable electron affinity range is typically limited. In this study, the authors develop a low-temperature atomic layer deposition (ALD) process to grow amorphous Sn1-xGaxOy thin films from dimethylamino-metal complexes and water. This oxide is predicted to provide a wide selection of possible electron affinity values, from around 3 eV for pure Ga2O3 to 4.5 eV for pure SnO2. The ALD process is evaluated for deposition temperatures in the range of 105-195 degrees C by in situ quartz crystal microbalance and with ex situ film characterization. The growth exhibits an ideal-like behavior at 175 degrees C, where the film composition can be predicted by a simple rule of mixture. Depending on film composition, the growth per cycle varies in the range of 0.6-0.8 angstrom at this temperature. Furthermore, the film composition for a given process appears insensitive to the deposition temperature. From material characterization, it is shown that the deposited films are highly resistive, fully amorphous, and homogeneous, with moderate levels of impurities (carbon, nitrogen, and hydrogen). By tailoring the metal cation ratio in films grown at 175 degrees C, the optical bandgap can be varied in the range from 2.7 eV for SnO2 to above 4.2 eV for Ga2O3. The bandgap also varies significantly as a function of deposition temperature. This control of properties indicates that Sn1-xGaxOy is a promising candidate for an electron transport layer material in a wide electron affinity range. Published by the AVS.

Place, publisher, year, edition, pages
A V S AMER INST PHYSICS, 2019
National Category
Condensed Matter Physics Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-390540 (URN)10.1116/1.5092877 (DOI)000472182400033 ()
Funder
Swedish Energy Agency, 2017-004796Swedish Research Council, 2017-00646 9Swedish Foundation for Strategic Research , RIF14-0053
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2020-01-08Bibliographically approved
Valovic, M., Andersson Sundén, E., Binda, F., Cecconello, M., Conroy, S., Ericsson, G., . . . Zychor, I. (2019). Control of the hydrogen:deuterium isotope mixture using pellets in JET. Nuclear Fusion, 59(10), Article ID 106047.
Open this publication in new window or tab >>Control of the hydrogen:deuterium isotope mixture using pellets in JET
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2019 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 59, no 10, article id 106047Article in journal (Refereed) Published
Abstract [en]

Deuterium pellets are injected into an initially pure hydrogen H-mode plasma in order to control the hydrogen: deuterium (H:D) isotope mixture. The pellets are deposited in the outer 20% of the minor radius, similar to that expected in ITER, creating transiently hollow electron density profiles. A H: D isotope mixture of approximately 45%:55% is obtained in the core with a pellet fuelling throughput of Phi(pel) = 0.045P(aux)/T-e,T-ped similar to previous pellet fuelling experiments in pure deuterium. Evolution of the H: D mix in the core is reproduced using a simple model, although deuterium transport could be higher at the beginning of the pellet train compared with the flat-top phase.

Keywords
tokamak, isotope mix control, pellet fuelling
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-399005 (URN)10.1088/1741-4326/ab3812 (DOI)000485675500001 ()
Funder
EU, Horizon 2020, 633053
Note

For complete list of authors see http://dx.doi.org/10.1088/1741-4326/ab3812

Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2019-12-13Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5815-3742

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