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  • 1. Andrault, D
    et al.
    Morard, G
    Bolfan-Casanova, N
    Ohtaka, O
    Fukui, H
    Arima, H
    Guignot, N
    Funakoshi, K
    Lazor, P
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Mezouar, M.
    Study of partial melting at high-pressure using in situ X-ray diffraction2006In: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 26, no 3, p. 267-276Article in journal (Refereed)
    Abstract [en]

    The high-pressure melting behavior of different iron alloys was investigated using the classical synchrotron-based in situ X-ray diffraction techniques. As they offer specific advantages and disadvantages, both energy-dispersive (EDX) and angle-dispersive (ADX) X-ray diffraction methods were performed at the BL04B1 beamline of SPring8 (Japan) and at the ID27-30 beamline of the ESRF (France), respectively. High-pressure vessels and pressure ranges investigated include the Paris- Edinburgh press from 2 to 17GPa, the SPEED-1500 multi-anvil press from 10 to 27 GPa, and the laser-heated diamond anvil cell from 15 to 60 GPa. The onset of melting (at the solidus or eutectic temperature) can be easily detected using EDX because the grains start to rotate relative to the X-ray beam, which provokes rapid and drastic changes with time of the peak growth rate. Then, the degree of melting can be determined, using both EDX and ADX, from the intensity of diffuse X-ray scattering characteristic of the liquid phase. This diffuse contribution can be easily differentiated from the Compton diffusion of the pressure medium because they have different shapes in the diffraction patterns. Information about the composition and/or about the structure of the liquid phase can then be extracted from the shape of the diffuse X-ray scattering.

  • 2. Azdouz, M
    et al.
    Azrour, M
    Manoun, B
    Bih, L
    El Ammari, L
    Benmokhtar, S
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Crystal structure and Raman Spectroscopy of NaKPbVO4 orthovanadates2009Conference paper (Other academic)
  • 3. Azdouz, M
    et al.
    Manoun, B
    Azrour, M
    Bih, L
    El Ammari, L
    Benmokhtar, S
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Synthesis, Rietveld refinements and Raman spectroscopy studies of the solid solution Na1-xKxPb4(VO4)(3) (0 <= x <= 1)2010In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 963, no 2-3, p. 258-266Article in journal (Refereed)
    Abstract [en]

    In the present study we report the synthesis, crystal structure and Raman spectroscopy studies of Na1-xKxPb4(VO4)(3) orthovanaclates solid solutions (0 <= x <= 1). Rielveld refinements showed that this solid solution is continuous adopting P6(3)/m (no. 176) space group. Some of Pb(II) cations are located in the (6 h) sites. The ninefold coordination sites (4f) are equally occupied by the other lead cations and the K+ and Na+ monovalent ions. The structure can be described as built up from [VO4](3-) tetrahedral and Ph2+ of sixfold coordination cavities (6 h positions), which delimit void hexagonal tunnels running along [0 0 1]. These tunnels are connected by cations of mixed sites (4f) half occupied by Pb(II) and half by Na+/K+ mixed cations. The existence of this type of lacunar apatite seems to be conditioned by the presence of lone pair cations Pb(II). Raman spectra of all the compositions are similar and show some linear shifts in band positions as a function of the composition toward high values due the substitutions of Na+ by K+ with a larger radius. No considerable changes in the temperature dependence of the Raman modes and the corresponding FWHM are observed and thus no temperature induced phase transition is observed in Na0.5K0.5Pb4(VO4)(3) up to 650 K.

  • 4. Azdouz, M
    et al.
    Manoun, B
    Bih, L
    Azrour, M
    Ait Hou, A
    Benmokhtar, S
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    On the crystal structure and high temperature Raman spectroscopy of Pb2BaP2O8 orthophosphate2009Conference paper (Other academic)
  • 5. Azdouz, M.
    et al.
    Manoun, B.
    Essehli, R.
    Azrour, M.
    Bih, L.
    Benmokhtar, S.
    Ait Hou, A.
    Lazor, P.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Crystal chemistry, Rietveld refinements and Raman spectroscopy studies of the new solid solution series: Ba3−xSrx(VO4)2 (0≤x≤3)2010In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 498, no 1, p. 42-51Article in journal (Refereed)
    Abstract [en]

    The new solid solution series Ba3-xSrx(VO4)(2) (0 <= x <= 3) has been synthesized and studied by a combination of X-ray powder diffraction and Raman vibrational spectroscopy. This continuous solid solution crystallise in the hexagonal system with R (3) over barm space group. The structure has been determined at room temperature from X-ray diffraction by the Rietveld method analysis. It is formed by a 3D network of (Ba/Sr)((1))(VO4)(2)(4-) layers linked into a crystal network by (Ba/Sr)(2+)((2)) cations. The vibrational spectra of this crystalline orthovanadate solid solution series are interpreted by means of factor group analysis in terms of space group R (3) over barm (D-3d(5)). Assignments of the V-O vibrational stretching and bending modes, as well as some of the external modes, have been made. While all the modes show a monotonous shift as a function of the composition x, a break in the curves of intensities, full width at half maximum and band areas as a function of x is observed and attributed to the statistical distribution of Ba and Sr ions in the same crystallographic sites.

  • 6.
    Bensaid, H.
    et al.
    LCMS, Laboratory of Chemistry of Solid Materials, Department of Chemistry, Faculty of Sciences, Ben M’Sik-Casablanca, Morocco.
    El Bouari, A.
    LCMS, Laboratory of Chemistry of Solid Materials, Department of Chemistry, Faculty of Sciences, Ben M’Sik-Casablanca, Morocco.
    Benmokhtar, S.
    LRCPGM, Research Laboratory of General Chemistry–Physics of Materials, Department of Chemistry, Faculty of Sciences, Ben M’Sik-Casablanca, Morocco.
    Manoun, B.
    LPCM, Laboratory of Physico-Chemistry of Materials, Department of Chemistry, FST Errachidia, Morocco.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Bih, L.
    LPCM, Laboratory of Physico-Chemistry of Materials, Department of Chemistry, FST Errachidia, Morocco.
    New molybdate Li2Co2xNix(MoO 4) 3 (0≤x≤2) materials with a lyonsite structure: X-ray diffraction and Raman spectroscopy studies2013In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1031, p. 152-159Article in journal (Refereed)
    Abstract [en]

    A solid solution was found to exist in the quaternary Li2O–CoO–NiO–MoO3 system between the two phases Li2Co2(MoO4)3 and Li2Ni2(MoO4)3. Both Li2Co2(MoO4)3 and Li2Ni2(MoO4)3 are isostructural with the mineral lyonsite, and substitution according to the formula Li2Co2−xNix(MoO4)3 (0 ⩽ x ⩽ 2) demonstrates that a complete solid solution exits. Rietveld analysis revealed that solid solution crystallizes at room temperature in orthorhombic space group Pnma (D2h). The structure shows that if the corners and edges octahedra share in the leaves, they share faces columns. Nickel and cobalt are shared statically in the trigonal prism and octahedral sites. The results of these compositions are consistent with studies where the Raman spectra. Therefore, all compositions are similar and show linear changes frequencies depending on the composition due to the substitution of Co2+ by Ni2+ with a larger radius.

  • 7.
    Bih, H.
    et al.
    1Département de Chimie, FST-Guéliz, Marrakech, Morocc.
    Bih, L.
    Equipe Sciences des matériaux, FST- Errachidia, B.P 509, Boutalamine, Morocco.
    Manoun, B.
    Equipe Sciences des matériaux, FST- Errachidia, B.P 509, Boutalamine, Morocco.
    Azrour, M.
    Equipe Sciences des matériaux, FST- Errachidia, B.P 509, Boutalamine, Morocco.
    Elouadi, B.
    LEACHIM, Université de La Rochelle, France.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Electrical Transport Properties Of Iodine Oxide Phosphate Glasses Issued From The NaI-Li2O-WO3-P2O5 System2010In: Moroccan Journal of Condensed Matter, ISSN 1114-2073, Vol. 12, p. 98-102Article in journal (Refereed)
    Abstract [en]

    Abstract: This work concerns the investigation of ion transport behaviour of NaI containing lithium tungstenphosphate glasses in order to understand better the role of NaI in the ionic cation transport. Glasses obtained in thesystem 0.5[x(2NaI)-(1-x)Li2O]-0.5[0.25(WO3)2-0.75P2O5] were investigated. The glass samples have beencharacterised using powder X-ray diffraction (XRD), thermal analysis, density and impedance spectroscopy. X-raydiffraction and thermal studies have confirmed that these glasses can be formed in the range x = 0 to 1. The mixedalkali glasses have shown higher activation energies and lower conductivities compared to single alkali doped glassesand this has been attributed to a mixed alkali effect.

  • 8. Bih, H
    et al.
    Bih, L
    Manoun, B
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    El Ammari, L
    Synthesis and structural study of a new ammonium phospho-molybdate hydrate2009Conference paper (Other academic)
  • 9. Bosi, Ferdinando
    et al.
    Skogby, Henrik
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Reznitskii, Leonid
    Atomic arrangements around the O3 site in Al- and Cr-rich oxytourmalines: a combined EMP, SREF, FTIR and Raman study2015In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 42, no 6, p. 441-453Article in journal (Refereed)
  • 10. Boye, S.A
    et al.
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Ahuja, R
    Physics, Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Magnetoresistance and Hall effect measurements of Ni to 6 GPa2005In: Journal of Magnetism and Magnetic Materials, Vol. 294, p. 347-358Article in journal (Refereed)
  • 11.
    Boye, S.A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Ahuja, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Magnetoresistance and Hall-effect measurements of Ni thin films2005In: Journal of Applied Physics, Vol. 97, p. 083902:1-5Article in journal (Refereed)
  • 12. Buiter, S.
    et al.
    Schreurs, G.
    Albertz, M.
    Beaumont, C.
    Burberry, C.
    Callot, Jean-Paul
    Cavozzi, C.
    Cerca, M.
    Chen, J.H.
    Cristallini, E.
    Cruden, A.
    Cruz, L.
    Cooke, M.
    Daniel, J.M.
    Egholm, D.
    Ellis, S.
    Gerya, T.
    Hodkinson, L.
    Hofmann, F.
    Garcia, V.H.
    Gomes, C.
    Grall, C.
    Guillou, H.
    Guzmán, C.
    Nur Hidayah, T.
    Hilley, G.
    Kaus, B.
    Klinkmüller, M.
    Koyi, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lu, C.Y.
    Macauley, J.
    Maillot, B.
    Meriaux, C.
    Mishin, Y.
    Nilfouroushan, Faramarz
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Pan, C.C.
    Pascal, C.
    Pillot, D.
    Portillo, R.
    Rosenau, R.
    Schellart, W.P.
    Schlische, R.
    Soulomiac, P.
    Take, A.
    Vendeville, B.
    Vettori, M.
    Vergnaud, M.
    Wang, S.H.
    Withjack, M.
    Yagupsky, D.
    Yamada, Y.
    Benchmarking the Sandbox: Quantitative Comparisons of Numerical and Analogue Models of Brittle Wedge Dynamics2010Conference paper (Refereed)
  • 13.
    Choudhury, Debraj
    et al.
    Solid State and Structural Chemistry Unit, and Department of Physics, at Indian Institute of Science, Bangalore, Indien.
    Mukherjee, S
    Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, Indien.
    Mandal, P
    Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Indien.
    Sundaresan, A
    Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Indien.
    Waghamare, U V
    Theoretical Science Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Indien.
    Bhattacharjee, Satadeep
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sharma, Ajay
    Department of Physics, Indian Institute of Science, Bangalore, Indien.
    Bhat, S V
    Department of Physics, Indian Institute of Science, Bangalore, Indien.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Sarma, Dipankar Das
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Tuning of dielectric properties and magnetism of SrTiO3 by site-specific doping of Mn2011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, no 12, p. 125124-Article in journal (Refereed)
    Abstract [en]

    Combining experiments with first-principles calculations, we show that site-specific doping of Mn into SrTiO(3) has a decisive influence on the dielectric properties of these doped systems. We find that phonon contributions to the dielectric constant invariably decrease sharply on doping at any site. However, a sizable, random dipolar contribution only for Mn at the Sr site arises from a strong off-centric displacement of Mn in spite of Mn being in a non-d(0) state; this leads to a large dielectric constant at higher temperatures and gives rise to a relaxor ferroelectric behavior at lower temperatures. We also investigate magnetic properties in detail and critically reevaluate the possibility of a true multiglass state in such systems.

  • 14. Dalton, D A
    et al.
    Wong, M
    Goncharov, A F
    Ojwang, J
    Struzhkin, V V
    Konopkova, Zuzana
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Thermal Emission Determination of Argon under Extreme Pressure and Temperature2011Conference paper (Refereed)
    Abstract [en]

    Argon is a common pressure-transmitting medium in diamond anvil cell (DAC) experiments, and is often used as thermal insulation in the laser heated DAC. A more thorough understanding of the thermal properties of argon under extreme conditions is essential for measuring thermal properties of materials under similar conditions. A transient heating technique was applied to a symmetric DAC up to 50 GPa and 2500 K. A 1 μm thick iridium foil positioned within a recessed gasket hole filled with argon served as a laser absorber to pump thermal energy into the sample. Pump pulses of 6 μs temporal width were provided from an electronically modulated Yb-based fiber laser. We determined the temperature of the coupler with 500 ns time resolution by applying a Planckian fit to the thermal emission spectrum. Finite element calculations were also used to simulate thermal diffusion in the DAC cavity. The experimental results show slightly larger thermal conductivity with theory, but the results converge in the limit of high temperature. This work is supported by NSF EAR 1015239, NSF-REU, Carnegie Institution of Washington, and DOE-NNSA (CDAC).

  • 15.
    Dubrovinsky, Leonid S.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Berggrundsgeologi.
    Saxena, Surendra K.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Berggrundsgeologi.
    Lazor, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Berggrundsgeologi.
    Weber, Hans-Peter
    Structure of beta-iron at high temperature and pressure1998In: Science, Vol. 281, p. 11a-Article in journal (Refereed)
  • 16.
    Dubrovinsky, LS
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Saxena, SK
    Haggkvist, P
    Weber, HP
    Le, Bihan T
    Hausermann, D
    Study of laser heated iron using third generation synchrotron X-ray radiation facility with imaging plate at high pressures1999In: PHYSICS AND CHEMISTRY OF MINERALS, ISSN 0342-1791, Vol. 26, no 7, p. 539-545Article in journal (Refereed)
  • 17.
    Dubrovinsky, LS
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Saxena, SK
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    High-pressure and high-temperature in situ X-ray diffraction study of iron and corundum to 68 GPa using an internally heated diamond anvil cell1998In: PHYSICS AND CHEMISTRY OF MINERALS, ISSN 0342-1791, Vol. 25, no 6, p. 434-441Article in journal (Refereed)
  • 18. Dubrovinsky, LS
    et al.
    Saxena, SK
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Stability of beta-iron: A new synchrotron X-ray study of heated iron at high pressure1998In: EUROPEAN JOURNAL OF MINERALOGY, ISSN 0935-1221, Vol. 10, no 1, p. 43-47Article in journal (Refereed)
    Abstract [en]

    We have conducted a new study on the stability of the beta-iron phase at high pressure and temperature. With the X-ray study of the electrically heated iron wire at pressures between 35 and 68 GPa, we are able to demonstrate the reversibility of transform

  • 19.
    Dubrovinsky, LS
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Saxena, SK
    Lazor, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Ahuja, R
    Eriksson, O
    Wills, JM
    Johansson, B
    Physics, Department of Physics.
    Experimental and theoretical identification of a new high-pressure phase of silica1997In: NATURE, ISSN 0028-0836, Vol. 388, no 6640, p. 362-365Article in journal (Refereed)
    Abstract [en]

    Following the discovery of stishovite (the highest-pressure polymorph of silica known from natural samples), many attempts have been made to investigate the possible existence of denser phases of silica at higher pressures. Based on the crystal structures

  • 20.
    Eddahaoui, K.
    et al.
    LCPGM, Laboratoire de Chimie-Physique Générale des Matériaux, Département de Chimie, Université Hassan II-Mohammedia, Faculté des Sciences Ben M’Sik, Casablanca, Morocco.
    Benmokhtar, S.
    LCPGM, Laboratoire de Chimie-Physique Générale des Matériaux, Département de Chimie, Université Hassan II-Mohammedia, Faculté des Sciences Ben M’Sik, Casablanca, Morocco.
    Manoun, B.
    Equipe Matériaux et Environnement, Laboratoire des Procédés de Valorisation des Ressources Naturelles, des Matériaux et Environnement, Université Hassan 1er Morocco, Morocco.
    Belaaouad, S.
    LCPGM, Laboratoire de Chimie-Physique Générale des Matériaux, Département de Chimie, Université Hassan II-Mohammedia, Faculté des Sciences Ben M’Sik, Casablanca, Morocco.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Vibrational Spectra and Factor Group Analysis of M0.50TiOPO4 Oxyphosphates (M = Mg, Zn, Ni, Co, Fe and Cu)2012In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 99, p. 81-89Article in journal (Refereed)
    Abstract [en]

    Raman spectra of a series of orthophosphates M0.50TiO(PO4) (M = Mg, Zn, Ni, Co, Fe, and Cu) have been recorded in crystalline state. Factor group analysis has been performed for space group P21/c and assignments of the internal modes of the [PO4] tetrahedra and [TiO6] octahedra have been made.

    Graphical abstract

  • 21.
    El Hachmi, Abdelhadi
    et al.
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco..
    Manoun, Bouchaib
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco.;Mohammed VI Polytech Univ, Mat Sci & Nanoengn Dept, Ben Guerir, Morocco..
    Tamraoui, Y.
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco.;Mohammed VI Polytech Univ, Mat Sci & Nanoengn Dept, Ben Guerir, Morocco..
    Mirinioui, F.
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco..
    Abkar, R.
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco..
    El Aamrani, M. A.
    Univ Hassan 1er, LS3M, FP Khouribga, Khouribga, Morocco..
    Saadoune, I.
    Mohammed VI Polytech Univ, Mat Sci & Nanoengn Dept, Ben Guerir, Morocco.;Univ Cadi Ayyad, FST Marrakech, LCME, Av A Khattabi, Marrakech 40000, Morocco..
    Sajieddine, M.
    Univ Sultan Moulay Sliman, Lab Phys & Mech Mat, Fac Sci & Tech, BP 523, Beni Mellal 23000, Morocco..
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Temperature induced structural phase transition in Sr3-xCaxFe2TeO9 (0 <= x <= 1) probed by Raman and Mossbauer techniques2017In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1141, p. 484-494Article in journal (Refereed)
    Abstract [en]

    A series of perovskites Sr3-xCaxFe2TeO9 (0 <= x <= 1) have been prepared in polycrystalline form by solid-state reaction method in air. These materials have been studied by X-ray powder diffraction method (XRPD) and Raman spectroscopy. An analysis of the XRD patterns at room temperature has shown that these compounds crystallize in a tetragonal system, space group I4/m. The structure contains alternating (Fe/Te)(2a)O-6 and (Fe/Te)(2b)O-6 octahedra, tilted in anti-phase in the basal ab-plane. The study of Raman spectroscopy at various temperatures shows a transition from tetragonal to cubic phase: I4/m -> Fm (3) over bar m. This phase transition occurs at high-temperature. Analysis of Raman spectra recorded at several temperatures shows that this phase transition appears near similar to 375 degrees C for (x = 0), similar to 435 degrees C for (x = 0.5) and similar to 451 degrees C for (x = 1). A proportional and gradual increase of temperature phase transition is observed as function of the calcium amount.

  • 22.
    El Hachmi, Abdelhadi
    et al.
    Univ Hassan Ier, LS3M, Khouribga 25000, Morocco.
    Tamraoui, Y.
    Univ Mohammed VI Polytech, Mat Sci & Nanoengn MSN, Lot 660 Hay Moulay Rachid, Ben Guerir 43150, Morocco;Univ Hassan Ier, LS3M, Khouribga 25000, Morocco.
    Manoun, Bouchaib
    Univ Mohammed VI Polytech, Mat Sci & Nanoengn MSN, Lot 660 Hay Moulay Rachid, Ben Guerir 43150, Morocco;Univ Hassan Ier, LS3M, Khouribga 25000, Morocco.
    Haloui, R.
    Univ Hassan Ier, LS3M, Khouribga 25000, Morocco.
    Elaamrani, M. A.
    Univ Hassan Ier, LS3M, Khouribga 25000, Morocco.
    Saadoune, I.
    Univ Mohammed VI Polytech, Mat Sci & Nanoengn MSN, Lot 660 Hay Moulay Rachid, Ben Guerir 43150, Morocco;Univ Cadi Ayyad, FST Marrakech, LCME, Av A Khattabi, Marrakech 40000, Morocco.
    Bih, L.
    Univ Moulay Ismail, Fac Sci Meknes, Equipe Phys Chim Matiere Condensee, PCMC, Meknes, Morocco.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Synthesis and Rietveld refinements of new ceramics Sr2CaFe2WO9 and Sr2PbFe2TeO9 perovskites2018In: Powder Diffraction, ISSN 0885-7156, E-ISSN 1945-7413, Vol. 33, no 2, p. 134-140Article in journal (Refereed)
    Abstract [en]

    Ceramics of Sr2CaFe2WO9 and Sr2PbFe2TeO9 double perovskites have been prepared in polycrystalline form by solid-state technique, in the air. The crystalline structure was analyzed using X-ray powder diffraction (XRPD) at room temperature. Rietveld analysis of XRPD) patterns show that both compounds adopt a tetragonal structure with space group I4/m, with unit cell parameters a = 5.5453(1) angstrom, c = 7.8389(1) angstrom for Sr(2)CaFc(2)WO(9), and a = 5.5994(15) angstrom, c = 7.8979(30) angstrom for Sr2PbFe2TeO9. A certain degree of anti-site disordering of W and/or Te and Fe on the B -sites have been detected, indicating the presence of a partial amount of W and/or Te at Fe positions and vice versa.

  • 23.
    Es-Soufi, H.
    et al.
    Univ Moulay Ismail, Equipe Physicochim Mat Condensee, PCMC, Fac Sci Meknes, Meknes, Morocco..
    Bih, L.
    Univ Moulay Ismail, Equipe Physicochim Mat Condensee, PCMC, Fac Sci Meknes, Meknes, Morocco..
    Manoun, B.
    Univ Hassan 1Er, Lab Sci Mat Mat & Modelisat LS3M, Settat 26000, Morocco.;Mohammed VI Polytech Univ, Mat Sci & Nanoengn Dept MSN, Lot 660 Hay Moulay Rachid, Ben Guerir 43150, Morocco..
    Lazor, P.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Structure, thermal analysis and optical properties of lithium tungsten-titanophosphate glasses2017In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 463, p. 12-18Article in journal (Refereed)
    Abstract [en]

    A melt-quenching method is used to prepare homogeneous glasses inside the 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(5) (x = 0, 5, 8,10 and 15 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-ray diffraction and differential scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. The determined parameters for the glasses such as density, molar volume and glass transition temperature (T-g) depend strongly on the chemical composition of the glasses. The density and T-g are found to decrease and increase with TiO2 content, respectively. Infrared (IR) spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap, E-g, and Lirbach energy, Delta E, were evaluated. The optical band gap is found to depend on the glass composition and it decreases as the content of the TiO2 increases. (C) 2017 Elsevier B.V. All rights reserved.

  • 24.
    Es-Soufi, H.
    et al.
    Fac Sci Meknes, Dept Chim, EquipePhys Chim Matiere Condensee PCMC, Meknes, Morocco..
    Bih, L.
    Fac Sci Meknes, Dept Chim, EquipePhys Chim Matiere Condensee PCMC, Meknes, Morocco..
    Manoun, B.
    Univ Hassan 1er, LS3M, Settat 26000, Morocco..
    Mezzane, D.
    Fac Sci & Tech Gueliz, LMCN, Marrakech, Morocco..
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Some physical properties of the glasses within the Li2O-Li2WO4-TiO2-P2O5 system2016In: Dielectric Materials And Applications, ISYDMA '2016 / [ed] Achour, ME Touahni, R Messoussi, R Elaatmani, M AitAli, M, MATERIALS RESEARCH FORUM LLC , 2016, p. 266-269Conference paper (Refereed)
    Abstract [en]

    Phosphate glasses of the compositions 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(3) (0 <= x <= 15, mol%) were prepared by the melt quenching method. The amorphous nature of these glasses was confirmed by the XRD diffraction. Their characteristic temperatures were determined by DSC analysis. Impedance spectroscopy is used to determine their electrical conductivity as a function of temperature. The obtained results show that the conductivity as a function of temperature follows an Arrhenius-law.

  • 25. Ezzahi, A
    et al.
    Azdouz, M
    Manoun, B
    Azrour, M
    Ider, A
    Bih, L
    Benmokhtar, S
    Ait Hou, A
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    On the crystal structure and high temperature Raman spectroscopy of Sr3-xPbxAs2O8 Series (0<x<3)2010Conference paper (Refereed)
  • 26. Goncharov, Alexander F.
    et al.
    Wong, Michael
    Dalton, D. Allen
    Ojwang, J. G. O.
    Struzhkin, Viktor V.
    Konopkova, Zuzana
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Thermal conductivity of argon at high pressures and high temperatures2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, no 11, p. 112609-Article in journal (Refereed)
    Abstract [en]

    Knowledge of the thermal conductivity of Ar under conditions of high pressures and temperatures (P-T) is important for model calculations of heat transfer in the laser heated diamond anvil cell (DAC) as it is commonly used as a pressure transmitting medium and for thermal insulation. We used a modified transient heating technique utilizing microsecond laser pulses in a symmetric DAC to determine the P-T dependent thermal conductivity of solid Ar up to 50 GPa and 2500 K. The temperature dependent thermal conductivity of Ar was obtained by fitting the results of finite element calculations to the experimentally determined time dependent temperature of a thin Ir foil surrounded by Ar. Our data for the thermal conductivity of Ar are larger than that theoretically calculated using the Green-Kubo formalism, but they agree well with those based on kinetic theory. These results are important for ongoing studies of the thermal transport properties of minerals at pressures and temperatures native to the mantle and core.

  • 27.
    Hudl, Matthias
    et al.
    KTH Royal Inst Technol, ICT Mat Phys, Electrum 229, SE-16440 Kista, Sweden..
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gavriliuk, Alexander G
    ETH, Dept Mat, CH-8093 Zurich, Switzerland; Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia.
    Struzhkin, Viktor
    Carnegie Inst Sci, Geophys Lab, Washington, DC 20015 USA.
    PPMS-based set-up for Raman and luminescence spectroscopy at high magnetic field, high pressure and low temperature2015In: EPJ Techniques and Instrumentation, ISSN 2195-7045, Vol. 2, no 1, article id 3Article in journal (Refereed)
    Abstract [en]

    We present an experimental set-up permitting Raman and luminescence spectroscopy studies in a commercial Physical Properties Measurement System (PPMS) from Quantum Design. Using this experimental set-up, gaseous, liquid and solid materials, in bulk or thin film form, may be investigated. The set-up is particularly suitable for the study of the spin-lattice coupling in strongly correlated oxide materials utilizing several different stimuli, e.g. magnetic and electric fields, high pressure and low temperatures. Details for the Raman extension, sample holder assembly and optical design, as well as data acquisition and measurement routine are described. Finally, we present exemplary results collected using the set-up, measured on reference materials, as well as on a correlated transition metal oxide.

  • 28.
    Hudl, Matthias
    et al.
    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.
    Nordblad, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ivanov, Sergey
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bazuev, G.V.
    nstitute of Solid-State Chemistry, Ural Branch of the Russian Academy of Science, Ekaterinburg, Russia.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Investigation of the magnetic phase transition and magnetocaloric properties of the Mn2FeSbO6 ilmenite2013In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 331, p. 193-197Article in journal (Refereed)
    Abstract [en]

    The magnetic phase transition and magnetocaloric properties of both mineral and synthetic melanostibite Mn2FeSbO6 with ilmenite-type structure have been studied. Mn2FeSbO6 orders ferrimagnetically below 270 K and is found to undergo a second-order magnetic phase transition. The associated magnetic entropy change was found to be 1.7 J/kg K for the mineral and 1.8 J/kg K for the synthetic melanostibite for 5 T field change. For the synthetic Mn2FeSbO6 the adiabatic temperature change was estimated from magnetic- and specific heat measurements and amounts to 0.2 K in 1 T field change. Perspectives of the functional properties of Mn2FeSbO6-based materials are discussed.

  • 29. Ivarsson, M.
    et al.
    Bengtson, S.
    Skogby, H.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Belivanova, V.
    Marone, F.
    Extensive bioweathering of secondary minerals in subseafloor basalts2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203Article in journal (Other academic)
  • 30.
    Ivarsson, Magnus
    et al.
    Swedish Museum Nat Hist, Dept Palaeobiol, SE-10405 Stockholm, Sweden.;Swedish Museum Nat Hist, Nord Ctr Earth Evolut, SE-10405 Stockholm, Sweden..
    Bengtson, Stefan
    Swedish Museum Nat Hist, Dept Palaeobiol, SE-10405 Stockholm, Sweden.;Swedish Museum Nat Hist, Nord Ctr Earth Evolut, SE-10405 Stockholm, Sweden..
    Skogby, Henrik
    Swedish Museum Nat Hist, Dept Geosci, SE-10405 Stockholm, Sweden..
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Broman, Curt
    Stockholm Univ, Dept Geol Sci, SE-10691 Stockholm, Sweden..
    Belivanova, Veneta
    Swedish Museum Nat Hist, Dept Palaeobiol, SE-10405 Stockholm, Sweden..
    Marone, Federica
    Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland..
    A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, article id e0140106Article in journal (Refereed)
    Abstract [en]

    We have after half a century of coordinated scientific drilling gained insight into Earth's largest microbial habitat, the subseafloor igneous crust, but still lack substantial understanding regarding its abundance, diversity and ecology. Here we describe a fossilized microbial consortium of prokaryotes and fungi at the basalt-zeolite interface of fractured subseafloor basalts from a depth of 240 m below seafloor (mbsf). The microbial consortium and its relationship with the surrounding physical environment are revealed by synchrotron-based X-ray tomographic microscopy (SRXTM), environmental scanning electron microscopy (ESEM), and Raman spectroscopy. The base of the consortium is represented by micro-stromatolites- remains of bacterial communities that oxidized reduced iron directly from the basalt. The microstromatolites and the surrounding basalt were overlaid by fungal cells and hyphae. The consortium was overgrown by hydrothermally formed zeolites but remained alive and active during this event. After its formation, fungal hyphae bored in the zeolite, producing millimetre-long tunnels through the mineral substrate. The dissolution could either serve to extract metals like Ca, Na and K essential for fungal growth and metabolism, or be a response to environmental stress owing to the mineral overgrowth. Our results show how microbial life may be maintained in a nutrient-poor and extreme environment by close ecological interplay and reveal an effective strategy for nutrient extraction from minerals. The prokaryotic portion of the consortium served as a carbon source for the eukaryotic portion. Such an approach may be a prerequisite for prokaryotic-eukaryotic colonisation of, and persistence in, subseafloor igneous crust.

  • 31. Konopkova, Z
    et al.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Goncharov, A F
    Struzhkin, V V
    Thermal conductivity of iron from laser-heated diamond anvill cell experiments2010Conference paper (Refereed)
  • 32. Konopkova, Z
    et al.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Tutti, Faramarz
    Thermal conductivity of iron under conditions of planetary interiors2008Conference paper (Refereed)
  • 33.
    Konopkova, Zuzana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Goncharov, Alexander
    Struzhkin, Viktor
    Determination of thermal conductivity of materials in laser-heated DAC2009In: Conference Booklet / [ed] A. Polian, M. Gauthier, S. Klotz, 2009, p. 117-Conference paper (Other academic)
    Abstract [en]

    Thermal conductivity of materials in planetary interiors belongs to key parameters controlling thermal evolution and dynamics of planets. Yet it is insufficiently constrained, in particular under the deep mantle and core conditions. For example, thermal conductivity of iron alloy in the Earth’s core has been recently revised by a factor of two [1]. Laser-heated diamond anvil cell technique offers, in principle, possibility for the experimental determination of thermal conductivity at extreme conditions, provided that the boundary conditions of sample assemblage are precisely characterized and controlled. Indeed, feasibility of such studies has been demonstrated in a number of heat-transfer simulations in DAC utilizing finite element method [e.g. 2], as well as in a recent pioneering study on the transient heat propagation facilitated by a pulsed laser heating [3].We will present results of steady-state heat transfer experiments combined with numerical simulations (COMSOL) on the high pressure thermal conductivity of iron in LHDAC, carried out in the HP laboratory as well as at the APS. We assess the effects of uncertainties and trade-offs between various parameters on the determination of conductivity. For the explored case of a thin foil of iron embedded in MgO, the key parameters, which have to be measured with a high precision and accuracy include radial temperature gradients on both sides of the foil, power distribution profile in the laser beam, and exact 3D geometry of the sample assemblage, including the pressure medium and adjacent gasket. Determination of the amount of absorbed laser power, especially at high temperatures, represents a challenge. State-of-the-art measurements will have to address also the effects of spatially varying thermal stress during a laser heating, and of the extrinsic anisotropy in thermal conductivity induced by preferred-orientation effects and a large uniaxial stress component. Diffusion, chemical reaction, and oxidation at the sample - pressure medium interface may result in the creation of a thin but potentially significant thermal barrier affecting the heat flow. We will discuss these issues and outline possibilities for a solution.

    [1] F. D. Stacey, D. E. Loper, Phys. Earth Planet. Int. 2007, 161, 13.[2] B. Kiefer, T. S. Duffy, J. Appl. Phys. 2005, 97, 114902.[3] P. Beck, A. F. Goncharov, V. V. Struzhkin, B. Militzer, H. K. Mao, R. J. Hemley, Appl. Phys. Lett. 2007, 91, 181914.

  • 34.
    Konopkova, Zuzana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Goncharov, Alexander
    Carnegie Institution of Washington, USA.
    Struzhkin, Viktor
    Carnegie Institution of Washington, USA.
    Thermal conductivity of iron in laser-heated DAC2010In: Conference Booklet, The 48th EHPRG Conference / [ed] R. Ahuja, C. Moyses Araujo, H. Löfås, 2010, p. 69-69Conference paper (Other academic)
  • 35.
    Konopkova, Zuzana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Struzhkin, V.V.
    Goncharov, A.F.
    Thermal conductivity of hcp iron at high pressure and temperature2011In: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 31, no 1, p. 228-236Article in journal (Refereed)
    Abstract [en]

    Results of steady-state heat transfer experiments on iron in laser-heated diamond anvil cell, combined with numerical simulation using finite-element method are reported. Thermal boundary conditions, dimensions of sample assemblage, heating-laser beam characteristics and relevant optical properties have been well defined in the course of experiments. The thermal conductivity of the polycrystalline hexagonal-iron foil has been determined up to pressure 70GPa and temperature 2000K. At these conditions, the conductivity value of 32 ± 7W/mK was found. Sources of errors arising from uncertainties in input parameters and applied experimental procedures are discussed. Considering results of earlier preferred-orientation studies in diamond anvil cell, an averaging effect of polycrystalline texture on the intrinsic anisotropy is assumed. The obtained conductivity is interpreted as an effective value, falling in between the upper and lower bounds on the average conductivity of a random aggregate of uniaxial crystals.

  • 36.
    Ladenberger, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Michalek, M
    CO2 fluid inclusions in mantle xenoliths from the Lower Silesia, SW Poland : investigations of fossil pressures in the upper mantle and decompression history of volcanic events2008Conference paper (Refereed)
  • 37.
    Ladenberger, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Michalik, Marek
    Institute of Geological Sciences, Jagiellonian University, Krakow, Poland.
    CO2 fluid inclusions in mantle xenoliths from Lower Silesia (SW Poland): formation conditions and decompression history2009In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 21, no 4, p. 751-761Article in journal (Refereed)
    Abstract [en]

    Raman spectroscopy has been applied to determine the density and pressure of formation of CO2 fluid inclusions in mantle xenoliths, carried to the surface at Wilcza Gora in southwestern Poland by early Miocene alkaline magmas. The magmas were generated by partial melting in the transition zone between the spinel and garnet stability fields. Determination of the densities of CO2 inclusions allows calculation of the partial pressures and reconstruction of the depth of xenolith origin as well as their history en route to the surface. The density of CO2 inclusions ranges from 0.06 to 1.10 g/cm(3) in olivines and 0.17 to 1.11 g/cm(3) in orthopyroxenes. Only inclusions with a density above 0.8 g/cm(3) reflect lower crust (ca. 15-30 km) and upper mantle (ca. 30-38 km) conditions. Slight differences in density of the inclusions between olivines and orthopyroxenes can be attributed to their different theological properties during magma ascent. Modelling of pressure and depth within the temperature range in which the xenoliths equilibrated with the magmas yields information about the complex eruption history of basanitic volcanoes. Our estimates are consistent with seismic data that show a regional high-velocity layer at the Moho (ca. 30-35 km deep) with p-wave velocities up to 8 km/s which have been attributed to mafic and ultramafic lithologies.

  • 38. Lahrich, S.
    et al.
    Elmhammedi, A.M.
    Manoun, B.
    Tamraoui, Y.
    Mirinioui, F.
    Azrour, M.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Elaboration, Rietveld refinements and vibrational spectroscopic study of Na1-xKxCaPb3(PO4)3 lacunar apatites (0 < x < 1)2015In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 145, p. 493-499Article in journal (Refereed)
    Abstract [en]

    Synthesis of apatites, Na1-xKxCaPb3(PO4)(3) 0 <= x <= 1, with anion vacancy were carried out using solid state reactions. The solid solution of apatite-type structure crystallize in the hexagonal system, space group P6(3)/m (No. 176). Rietveld refinements showed that around 90% of Pb2+ cations are located in the (6h) sites, the left amount of Pb2+ cations are located in the (4f) sites; 27-31% of Ca2+ cations are located in the (6h) sites, the left amount of Ca2+ cations are located in the (4f) sites. The ninefold coordination sites (4f) are also occupied by the K+ and Na+ monovalent ions. The structure can be described as built up from [PO4](3-) tetrahedra and Pb2+/Ca2+ of sixfold coordination cavities (6h positions), which delimit void hexagonal tunnels running along [001]. These tunnels are connected by cations of mixed sites (4f) which are half occupied by Pb2+/Ca2+ and half by Na+/K+ mixed cations. The assignment of the observed frequencies in the Raman and infrared spectra is discussed on the basis of a unit cell group analysis and by comparison with other apatites. Vibrational spectra of all the compositions are similar and show some linear shifts of the frequencies as a function of the composition toward lower values due the substitutions of Na+ by K+ with a larger radius.

  • 39.
    Lazor, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Saxena, S
    Dubrovinsky, L
    Weber, HP
    LeBihan, T
    Synchrotron X-ray Diffraction of Iron under High Pressure and Temperature2000In: Proceedings of the AIRAPT-17, Honolulu, Hawaii, July 1999, 2000, p. 1059-1062Conference paper (Refereed)
  • 40.
    Lazor, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Saxena, SK
    Discussion comment on melting criteria and imaging spectroradiometry in laser-heated diamond-cell experiments1996In: PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol. 354, no 1711, p. 1307-1313Article in journal (Refereed)
  • 41.
    Lazor, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Shen, G
    Saxena, SK
    Laser-Heated Diamond Anvil Cell Experiments at High Pressure: Melting Curve of Nickel to 700 kbar1993In: Phys. Chem. Minerals, Vol. 20, p. 86-90Article in journal (Refereed)
  • 42.
    Lazor, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Berggrundsgeologi.
    Mineralen i jordens inre: Hur ser de ut och hur vet vi det?2005In: Geologiskt forum, ISSN 1104-4721, Vol. 12, no 47, p. 42-47Article in journal (Other (popular scientific, debate etc.))
  • 43.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Precise optical interferometry in DAC: Application to dielectric and equation-of-state studies2007Conference paper (Other academic)
    Abstract [en]

    In the past the technique of white-light interferometry in a diamond anvil cell proved to represent a reliable tool for measurements of pressure dependence of the optical dielectric function. We have re-examined the precision and accuracy of this technique and applied it to refractive-index studies on H2O and other molecular and simple solids. We will show that this technique, when combined with fitting transmission spectra by the Airy function, allows precise measurements of weak dispersion effects in transparent materials, as well as determination of distance between diamond anvils at a submicron resolution. Additionally, application of the interferometry together with an image analysis of sample facilitated complete monitoring and control of pressure-volume-temperature conditions of studied H2O ices. It will be shown that this method represents a promising tool for the determination of equations of state of optically transparent liquids and soft solids in a diamond anvil cell.

  • 44.
    Lazor, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Temperature measurement in a laser-heated DAC2001In: Program of Symposium on Advanced Materials 2001: Ultra-High Pressure Research, 2001, p. 45-46Conference paper (Refereed)
  • 45.
    Lazor, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Hudl, Matthias
    Struzhkin, Viktor
    Nordblad, Per
    Svedlindh, Peter
    Somayazulu, Maddury
    Raman spectroscopy at extreme conditions for fundamental and materials characterization studies2010Conference paper (Refereed)
  • 46.
    Lazor, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Mao, H K
    Mao, W L
    Shu, J
    Hu, M Y
    Chou, P
    Somayazulu, M
    Hemley, R J
    X-ray induced dissociation of NH3 at high pressure2007Conference paper (Refereed)
  • 47.
    Lazor, Peter
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Shebanova, Olga
    Annersten, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    High-pressure study of stability of magnetite by thermodynamic analysis and synchrotron x-ray diffraction2004In: 26th Nordic Geological Winter Meeting: Abstracts, 2004, p. 43-44Conference paper (Refereed)
  • 48.
    Lazor, Peter
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology. Berggrundsgeologi.
    Shebanova, Olga
    Annersten, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Stability of iron oxides in Earth's mantle2004In: Proceedings of the 32nd International Geological Congress: Abstracts, 2004Conference paper (Refereed)
    Abstract [en]

    Synchrotron x-ray diffraction, Raman spectroscopic experiments, and thermodynamic analysis aiming at the investigation of stability of iron oxides at pressures and temperatures reaching the deep lower mantle conditions were carried out using diamond anvil cell technique combined with laser and resistive heating. In the x-ray experiments, the thermodynamically predicted breakdown of magnetite to hematite and wüstite was not observed, but the trace amounts of hematite detected in the sample assemblage may signify the presence of nucleation centers of breakdown products, the growth of which is kinetically hindered due to the energetic requirements for the reaction. This is corroborated by the occurrence of bands of the locally ordered units of hematite in the Raman spectra. Raman spectra of wüstite compressed to 80 GPa and subjected to an intense laser heating show several new strong bands in the range 200-350 , originating presumably from the transformation to a polymorph with the NiAs structure. The transition is reversible as evidenced by the recovery of wüstite upon decompression of sample to a zero pressure. The 298 K isotherm of magnetite derived from the compression experiments is in a very good agreement with the results of earlier studies. The 1-confidence ellipsoid shows large negative correlations for the fit parameters K0, K0', and V0. The transformation of magnetite to a dense polymorph was observed already at 19 GPa. The Rietveld refinement of the diffraction pattern of is consistent with the -type structure. Thermodynamic assessment shows that on the pressure - temperature phase diagram the stability field for the mixture of oxides + FeO has maximum temperature of only 850 K at 14.6 GPa. At 298 K, the equilibrium pressure for the breakdown of magnetite is 13.3 GPa, while the pressure for the synthesis of FeO + to is located between 35 and 47 GPa, depending on the choice of the equation of state. The calculations also predict that the becomes unstable with respect to h- + FeO at pressures higher than 50 GPa. The values of Gibbs formation energies at standard conditions for the high-pressure polymorphs and h- were estimated to be -962 kJ/mol and -610 kJ/mol, respectively. The standard-state entropy of is 172.4 J/K/mol.

  • 49.
    Li, Nana
    et al.
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China..
    Manoun, Bouchaib
    Univ Hassan Ler, Lab Sci Mat Milieux & Modelisat LS3M, Khouribga 25000, Morocco..
    Tang, Lingyun
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China.;Carnegie Inst Sci, Geophys Lab, High Pressure Synerget Consortium, Argonne, IL 60439 USA..
    Ke, Feng
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China..
    Liu, Fengliang
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China.;Fudan Univ, State Key Lab Surface Phys, Dept Phys, Shanghai 200433, Peoples R China.;Fudan Univ, Adv Mat Lab, Shanghai 200433, Peoples R China..
    Dong, Haini
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China.;Chinese Acad Sci, Inst Geochem, Key Lab High Temp & High Pressure Study Earth Int, Guizhou 550081, Peoples R China..
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Yang, Wenge
    Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China.;Carnegie Inst Sci, Geophys Lab, High Pressure Synerget Consortium, Argonne, IL 60439 USA..
    Pressure-Induced Structural and Electronic Transition in Sr2ZnWO6 Double Perovskite2016In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 55, no 13, p. 6770-6775Article in journal (Refereed)
    Abstract [en]

    High-pressure structural and electrical properties of Sr2ZnWO6 double perovskite were investigated using in situ angle-dispersive synchrotron X-ray diffraction (XRD), Raman, and alternating current (AC) impedance spectroscopy. A structural transition from monoclinic (P2(1)/n) to triclinic (P (1) over bar) phase around 9 GPa was observed due to the pressure-induced distortion of (W, Zn)O-6 octahedron. In situ high-pressure Raman spectroscopy showed the increasing interaction among O-W-O in WO6 octahedron with pressure and a transition pressure consistent with the XRD results. From the AC impedance spectroscopy measurements, the resistivity increased steeply by similar to 1 order of magnitude around 11 GPa, indicating an electronic transition accompanying the symmetry change. The increase in the interaction among O-W-O enhances the attraction of O2- electrons toward W6+, thus increasing the covalence, which in turn lowers the charge transfer energy between O2- and W6+ and induces the resistivity increase under high pressure.

  • 50. Manoun, B.
    et al.
    Azdouz, M.
    Azrour, M.
    Essehli, R.
    Benmokhtar, S.
    Ammari, L. El
    Ezzahi, A. Ider
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Synthesis, Rietveld refinements and Raman spectroscopic studies of tricationic lacunar apatites Na1-xKxPb4(AsO4)3 (0 ≤ x ≤ 1)2010In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 986, no 1-3, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Three compounds from the solid solution of lead lacunar ionic apatites Na1−xKxPb4(AsO4)3, with x = 0, 0.5 and 1, were successfully synthesized as single phases by solid state method at 700 °C. The samples were characterized by X-ray diffraction, the site of the metal ions (Na+, K+ and Pb2+) in the solid solutions was analyzed with the Rietveld method. A variation of the a and c lattice parameters in the solid solutions was observed, with an increase of a and c parameters, related to the radius of the corresponding substituted ions. It was found that Pb(II) ions in the solid solutions preferentially occupied the M(1) and M(2) sites in the lacunar anionic apatite structure. The structure contains channels running along the c axis and centred at (0 0 z). The channels are most probably occupied by the lone electron pairs of the Pb2+ cations. Raman spectra of all the compositions are similar and show some linear shifts, especially for the bending modes, in band positions as a function of the composition toward lower values due the substitutions of Na+ by K+ with a larger radius. No considerable changes in the temperature dependence of the Raman modes and the corresponding FWHM are observed and thus no temperature induced phase transition is observed in Na0.5K0.5Pb4(AsO4)3 up to 630 K.

12 1 - 50 of 97
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