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Pressure effects in lutetium yttrium oxyorthosilicate single crystals
Author(s) -
Ricci Pier Carlo,
Chiriu Daniele,
Carbonaro Carlo Maria,
Desgreniers Serge,
Fortin Emery,
Anedda Alberto
Publication year - 2008
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1986
Subject(s) - monoclinic crystal system , raman spectroscopy , hydrostatic pressure , phase (matter) , ambient pressure , atmospheric pressure , yttrium , analytical chemistry (journal) , volume (thermodynamics) , phase transition , materials science , raman scattering , chemistry , crystal (programming language) , lutetium , crystal structure , crystallography , thermodynamics , optics , geology , organic chemistry , metallurgy , physics , oceanography , oxide , programming language , computer science
The Raman scattering from Lu 1.8 Y 0.2 SiO 5 single crystals was investigated for quasi‐hydrostatic pressures ranging from atmospheric to about 15 GPa at room temperature. The material, originally belonging to the monoclinic C 2/ c structure, transforms gradually to a higher‐density phase upon the application of pressure. Unit cell volume, peak position, and the Grüneisen parameter have been calculated and analyzed, revealing three different pressure regimes. The first low‐pressure regime relates mainly to the change of unit cell volume. In the second pressure regime, the gradual phase transformation starts at about 3 GPa and is completed at a pressure of 10 GPa. The third pressure regime part reveals a sensibly lower pressure dependence. A detailed analysis of the data allowed us to propose a scheme for a pressure‐induced gradual phase transition, resulting in the coexistence of phases over a wide pressure range. Moreover, the material reverts to the ambient‐condition phase upon release of pressure, showing an almost total reversibility. By comparison with the vibrational spectra of the pure Y 2 SiO 5 compound and from the analysis of the crystal structures, the pressure‐induced high‐density phase is assigned to the P 2 1 / c monoclinic structure, typical of oxyorthosilicates. Copyright © 2008 John Wiley & Sons, Ltd.