Zobrazeno 1 - 10
of 85
pro vyhledávání: '"J.-Y. Gesland"'
Publikováno v:
Ferroelectrics. 334:57-65
Czochralski-grown Li 3 ThF 7 single crystals were investigated by X-ray diffraction and polarized optical microscopy. The crystals show an ordered pattern of micro-cracks, which appear just after their growth. Besides the thermal dependence of the la
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::4c5a35da527c7bd32c12ac98612bcbf4
https://doi.org/10.1080/00150190600689811
https://doi.org/10.1080/00150190600689811
Publikováno v:
Journal of Physics: Condensed Matter. 18:2511-2523
Dielectric constant and ionic conductivity measurements have been performed in SrAlF5 single crystals, along the [100] and [001] directions, as functions of frequency (10 Hz–10 MHz) and temperature (300–800 K). The real part of the ac conductivit
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ff4a99792bfb6e8e6c6d502aa23bc793
https://doi.org/10.1088/0953-8984/18/8/014
https://doi.org/10.1088/0953-8984/18/8/014
Publikováno v:
Vibrational Spectroscopy. 39:244-248
Polarized infrared-reflectivity spectra have been obtained for Czochralski-grown YF 3 and LuF 3 single crystals, at room temperature. At this temperature these crystals exhibit an orthorhombic symmetry belonging to the Pnma ( D 2 h 16 ) space group,
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b47d61742177590d81895db4ba8b74f8
https://doi.org/10.1016/j.vibspec.2005.04.010
https://doi.org/10.1016/j.vibspec.2005.04.010
Publikováno v:
Journal of Physics: Condensed Matter. 16:7511-7520
SrAlF5 has been considered as one of the rare fluoride ferroelectric crystals, belonging to the polar I4 group. However, recent x-ray diffraction data suggest that the correct structure is centrosymmetric (I41/a). Since ferroelectricity is forbidden
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9f717c9cca7473a716ecd13d0743cf4c
https://doi.org/10.1088/0953-8984/16/41/028
https://doi.org/10.1088/0953-8984/16/41/028
Autor:
M. Grimsditch, I. Guedes, E. A. Oliveira, Alejandro Ayala, Roberto L. Moreira, Javier Ellena, J.-Y. Gesland
Publikováno v:
Journal of Solid State Chemistry. 177:2943-2950
The crystalline structure of NaCaMg 2 F 7 was determined using single crystal X-ray diffraction. This compound crystallizes in the cubic pyrochlore structure, i.e., space group Fd 3 m , lattice parameter: a=10.2610(5) A and Z =8. All atoms occupy spe
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e04a1aa1e654dd5d75511862ee8f3bb3
https://doi.org/10.1016/j.jssc.2004.04.055
https://doi.org/10.1016/j.jssc.2004.04.055
Autor:
Roberto L. Moreira, Carlos William de Araujo Paschoal, Alejandro Ayala, J.-Y. Gesland, I. Guedes
Publikováno v:
Solid State Communications. 129:539-543
In this work we employ calorimetric and dielectric techniques to study the sequence of structural phase transitions (SPTs) of CsInF4 crystal in the temperature range from 450 to 250 K. Our results show three first-order SPTs. Based on these results a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ab299e3b62a254486ef7fea256b16afe
https://doi.org/10.1016/j.ssc.2003.11.013
https://doi.org/10.1016/j.ssc.2003.11.013
Autor:
J. Mendes Filho, J.-Y. Gesland, Roberto L. Moreira, Edson Holanda Teixeira, Alejandro Ayala, F. E. A. Melo, Carlos William de Araujo Paschoal
Publikováno v:
Vibrational Spectroscopy. 31:159-166
Single crystals of the Na 2 ThF 6 hexafluor metallate were studied by polarized infrared reflectivity and Raman scattering. This compound belongs to the P 321 ( D 3 2 ) space group and, contrary to most of the members of A 2 MX 6 family, it is not ch
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::941b0986e6ec21076a1ad08a7db7584b
https://doi.org/10.1016/s0924-2031(03)00012-2
https://doi.org/10.1016/s0924-2031(03)00012-2
Autor:
Alejandro Ayala, Javier Ellena, Carlos William de Araujo Paschoal, Eduardo E. Castellano, Roberto L. Moreira, J.-Y. Gesland
Publikováno v:
Journal of Physics: Condensed Matter. 14:5485-5495
The room-temperature crystal structure of Li2CaHfF8 is determined using high-precision single-crystal x-ray diffraction measurements. It is found to be tetragonal, belonging to the space group I with Z = 2. The cell parameters are a = 5.1063(2) A and
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::00a738efa10261707798f18957f10268
https://doi.org/10.1088/0953-8984/14/22/303
https://doi.org/10.1088/0953-8984/14/22/303
Autor:
J.-Y. Gesland, M. A. C. Machado, Roberto L. Moreira, Alejandro Ayala, Carlos William de Araujo Paschoal, J. Mendes Filho
Publikováno v:
Journal of Physics: Condensed Matter. 14:271-280
Single crystals of the Li3Na3In2F12 fluoride garnet have been studied by Fourier-transform infrared spectroscopy and Raman scattering. Polarized Raman spectra were recorded at low temperatures showing that the room-temperature phase is stable down to
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5582b43ada8ec6a6cddfbdcdca904631
https://doi.org/10.1088/0953-8984/14/2/313
https://doi.org/10.1088/0953-8984/14/2/313
Autor:
J. Y. Gesland, R. L. Moreira, C. J. Franco, Maurício V. B. Pinheiro, M. A. S. Oliveira, K. J. Guedes, K. Krambrock
Publikováno v:
Scopus-Elsevier
Electron Paramagnetic Resonance (EPR) and Raman Spectroscopy were used to study the low temperature phase transition of pulled Li 3 ThF 7 single crystals, occurring at 281 K. In both cases, the room temperature spectra were very broad, owing to the s
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a1f1b3a8bb9e3173fa7524b369a1b3ee
https://doi.org/10.1080/10420150108214138
https://doi.org/10.1080/10420150108214138