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Manoun, B., Tamraoui, Y., Saadoune, I., Lazor, P., Yang, W. & Alami, J. (2017). Crystal structure and high temperature Raman spectroscopy of Sr2ZnTeO6 double perovskite. MATERIALS RESEARCH EXPRESS, 4(10), Article ID 105018.
Open this publication in new window or tab >>Crystal structure and high temperature Raman spectroscopy of Sr2ZnTeO6 double perovskite
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2017 (English)In: MATERIALS RESEARCH EXPRESS, ISSN 2053-1591, Vol. 4, no 10, article id 105018Article in journal (Refereed) Published
Abstract [en]

Sr2ZnTeO6 double-perovskite oxide has been synthesized using solid state chemistry. As synthesized, the crystalline structure of Sr2ZnTeO6, refined using x-ray diffraction, is monoclinic having the space group I2/m. Structural phase transitions are studied using Raman spectroscopy in the temperature range 25 degrees C-567 degrees C. It is found that two of three observed bending Raman vibrations merge together at a temperature of around 120 degrees C, indicating a Sr2ZnTeO6 phase transition from the monoclinic (I2/m) to the tetragonal (I4/m). Furthermore, a temperature-dependence change-rate of external and O-Te-O bending modes and stretching modes are detected at 270 degrees C, which is interpreted as a phase transition from the tetragonal (I4/m) to the cubic (Fm-3m) structure.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2017
Keywords
double perovskite, phase transition, Raman spectroscopy, Sr2ZnTeO6
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-342607 (URN)10.1088/2053-1591/aa8d87 (DOI)000415251700004 ()
Funder
Swedish Research Council, 348-2014-4287
Available from: 2018-02-23 Created: 2018-02-23 Last updated: 2018-02-23Bibliographically approved
Es-Soufi, H., Bih, L., Manoun, B. & Lazor, P. (2017). Structure, thermal analysis and optical properties of lithium tungsten-titanophosphate glasses. Journal of Non-Crystalline Solids, 463, 12-18
Open this publication in new window or tab >>Structure, thermal analysis and optical properties of lithium tungsten-titanophosphate glasses
2017 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 463, p. 12-18Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Phosphate, Glasses, DSC, IR spectroscopy, Optical properties
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-330050 (URN)10.1016/j.jnoncrysol.2017.02.013 (DOI)000405154700003 ()
Available from: 2017-11-09 Created: 2017-11-09 Last updated: 2017-11-09Bibliographically approved
Tamraoui, Y., Manoun, B., Mirinioui, F., Saadoune, I., Haloui, R., Elhachmi, A., . . . Lazor, P. (2017). Temperature and composition induced phase transitions in Sr2-xCa1+xTeO6 (0 <= x <= 2) double perovskite oxides. Journal of Molecular Structure, 1131, 103-113
Open this publication in new window or tab >>Temperature and composition induced phase transitions in Sr2-xCa1+xTeO6 (0 <= x <= 2) double perovskite oxides
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2017 (English)In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1131, p. 103-113Article in journal (Refereed) Published
Abstract [en]

Structures of Sr2-xCa1+xTeO6 double perovskites have been studied by the profile analysis of X-ray diffraction data and Raman spectroscopy at room temperature. This series adopts a monoclinic symmetry for the compositions (0 <= x <= 0.5) with P2(1)/n as space group and a triclinic system with P (1) over bar space group for the compositions (0.5 < x <= 2). These results were confirmed by the observed tolerance factor calculated from the distances obtained from the Rietveld refinements which indicates that the true tilt system for the compositions range (0.5 < x <= 2) is the triclinic tilt system. Clear changes in the Raman modes centered at 600, 610 and 620 cm(-1) and the FWHM of O-Te-O bending vibrations, centered at 738 cm(-1) confirmed that the triclinic symmetry takes place between the compositions x = 0.5 and x = 1. Furthermore, Raman spectroscopy studies at high temperature were done for Ca3TeO6. For this compound, considerable changes in the temperature dependence of the modes were well illustrated.

Keywords
Inorganic compounds, X-ray diffraction, Raman spectroscopy, Crystal structure, Phase transition
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-316406 (URN)10.1016/j.molstruc.2016.11.036 (DOI)000392683600012 ()
Funder
Swedish Research Council, 348- 2014-4287
Available from: 2017-03-02 Created: 2017-03-02 Last updated: 2017-11-29Bibliographically approved
El Hachmi, A., Manoun, B., Tamraoui, Y., Mirinioui, F., Abkar, R., El Aamrani, M. A., . . . Lazor, P. (2017). Temperature induced structural phase transition in Sr3-xCaxFe2TeO9 (0 <= x <= 1) probed by Raman and Mossbauer techniques. Journal of Molecular Structure, 1141, 484-494
Open this publication in new window or tab >>Temperature induced structural phase transition in Sr3-xCaxFe2TeO9 (0 <= x <= 1) probed by Raman and Mossbauer techniques
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2017 (English)In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1141, p. 484-494Article in journal (Refereed) Published
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.

Keywords
Double perovskite, Crystal structure, Phase transition, X-ray diffraction, Raman spectroscopy, Mossbauer spectroscopy
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-323746 (URN)10.1016/j.molstruc.2017.03.118 (DOI)000401593400057 ()
Funder
Swedish Research Council, 348-2014-4287
Available from: 2017-06-13 Created: 2017-06-13 Last updated: 2017-06-13Bibliographically approved
Sinouh, H., Bih, L., Manoun, B. & Lazor, P. (2017). Thermal analysis and crystallization of the glasses inside the BaO-SrO-TiO2-NaPO3 system. Journal of thermal analysis and calorimetry (Print), 128(2), 883-890
Open this publication in new window or tab >>Thermal analysis and crystallization of the glasses inside the BaO-SrO-TiO2-NaPO3 system
2017 (English)In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 128, no 2, p. 883-890Article in journal (Refereed) Published
Abstract [en]

The xBa(0.5)Sr(0.5)TiO(3)-(1 - x)NaPO3 (x = 0-0.20 mol%) glasses were prepared by the conventional melt-quenching method. The amorphous state of the samples was verified by X-ray diffraction. The density, molar volume, glass transition temperature (T (g)), micro-hardness and the crystallization temperature (T (c)) are determined for each glass. It is found that they depend strongly on the chemical composition of the glasses. The results of the micro-hardness show an increase in the H (v) parameter with the Ba0.5Sr0.5TiO3 content. The crystallization of glasses is made by submitting samples to heat treatments, and the crystallized phases are identified by XRD. The kinetic of the crystallization is carried out by thermal analysis using DSC technique. The mechanism of crystallization is proposed according to the determined activation energy (E (a)) and the Avrami parameter (n). The structural approach of the glasses was realized out by IR spectroscopy. This technique has highlighted the co-existence of different phosphate and titanium structural units in the glassy-matrix.

Place, publisher, year, edition, pages
SPRINGER, 2017
Keywords
Phosphate, Glasses, Glass-ceramics, Crystallization, Kinetic, Thermal analysis
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-322168 (URN)10.1007/s10973-016-5986-5 (DOI)000399242400027 ()
Funder
Swedish Research Council
Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-05-17Bibliographically approved
Weis, F. A., Lazor, P., Skogby, H., Stalder, R. & Eriksson, L. (2016). Polarized IR and Raman spectra of zoisite: insights into OH-dipole orientation and the luminescence. European journal of mineralogy, 28(3), 537-543
Open this publication in new window or tab >>Polarized IR and Raman spectra of zoisite: insights into OH-dipole orientation and the luminescence
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2016 (English)In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 28, no 3, p. 537-543Article in journal (Refereed) Published
Abstract [en]

The OH-dipole in the mineral zoisite has been a topic of discussion regarding its general orientation and vibrational modes. We present new polarized single-crystal Raman and infrared spectra and verify the orientation of the OH-dipole along the crystallographic c axis with a slight deviation towards the crystallographic a axis. Polarized Raman and FTIR spectra confirm that the OH band at 3150 cm(-1) corresponds to the O(10)-H center dot center dot center dot O(4) hydrogen bridge and exclude a previously suggested second hydrogen bridge O(10)-H center dot center dot center dot O(2). Further, Raman spectra provide insights on the luminescence of zoisite and the interference of luminescence peaks in the OH-region.

National Category
Geochemistry
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-271067 (URN)10.1127/ejm/2016/0028-2528 (DOI)000385334200003 ()
Available from: 2016-01-05 Created: 2016-01-05 Last updated: 2017-12-01Bibliographically approved
Li, N., Manoun, B., Tang, L., Ke, F., Liu, F., Dong, H., . . . Yang, W. (2016). Pressure-Induced Structural and Electronic Transition in Sr2ZnWO6 Double Perovskite. Inorganic Chemistry, 55(13), 6770-6775
Open this publication in new window or tab >>Pressure-Induced Structural and Electronic Transition in Sr2ZnWO6 Double Perovskite
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2016 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 55, no 13, p. 6770-6775Article in journal (Refereed) Published
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.

National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:uu:diva-301025 (URN)10.1021/acs.inorgchem.6b01091 (DOI)000379455900052 ()27308777 (PubMedID)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IG2010-2062
Available from: 2016-08-17 Created: 2016-08-17 Last updated: 2017-11-28Bibliographically approved
Es-Soufi, H., Bih, L., Manoun, B., Mezzane, D. & Lazor, P. (2016). Some physical properties of the glasses within the Li2O-Li2WO4-TiO2-P2O5 system. In: Achour, ME Touahni, R Messoussi, R Elaatmani, M AitAli, M (Ed.), Dielectric Materials And Applications, ISYDMA '2016: . Paper presented at 1st International Symposium on Dielectric Materials and Applications (ISyDMA 2016), MAY 04-06, 2016, MOROCCO (pp. 266-269). MATERIALS RESEARCH FORUM LLC
Open this publication in new window or tab >>Some physical properties of the glasses within the Li2O-Li2WO4-TiO2-P2O5 system
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2016 (English)In: 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, Published 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.

Place, publisher, year, edition, pages
MATERIALS RESEARCH FORUM LLC, 2016
Series
Materials Research Proceedings, ISSN 2474-395X ; 1
Keywords
Phosphate, Tungstate, Glasses, Glass Transition Temperature, Conductivity
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-321276 (URN)10.21741/2474-395X/1/66 (DOI)000396293900066 ()9781945291180 (ISBN)
Conference
1st International Symposium on Dielectric Materials and Applications (ISyDMA 2016), MAY 04-06, 2016, MOROCCO
Available from: 2017-05-02 Created: 2017-05-02 Last updated: 2017-05-02Bibliographically approved
Ivarsson, M., Bengtson, S., Skogby, H., Lazor, P., Broman, C., Belivanova, V. & Marone, F. (2015). A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust. PLoS ONE, 10(10), Article ID e0140106.
Open this publication in new window or tab >>A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust
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2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, article id e0140106Article in journal (Refereed) Published
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.

National Category
Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-267207 (URN)10.1371/journal.pone.0140106 (DOI)000363248400044 ()26488482 (PubMedID)
Funder
Swedish Research Council, 2010-3929Swedish Research Council, 2012-4364Paul Scherrer Institut, PSI, 20130185Paul Scherrer Institut, PSI, 20141047
Available from: 2015-11-19 Created: 2015-11-19 Last updated: 2017-12-01Bibliographically approved
Bosi, F., Skogby, H., Lazor, P. & Reznitskii, L. (2015). Atomic arrangements around the O3 site in Al- and Cr-rich oxytourmalines: a combined EMP, SREF, FTIR and Raman study. Physics and chemistry of minerals, 42(6), 441-453
Open this publication in new window or tab >>Atomic arrangements around the O3 site in Al- and Cr-rich oxytourmalines: a combined EMP, SREF, FTIR and Raman study
2015 (English)In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 42, no 6, p. 441-453Article in journal (Refereed) Published
National Category
Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240997 (URN)10.1007/s00269-015-0735-z (DOI)000354480300003 ()
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2017-12-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9992-8009

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