1. High pressure effects on the structural and vibrational properties of antiferromagnetic KFe(MoO4)2
- Author
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Adam Pietraszko, Paweł E. Tomaszewski, Paulo Freire, A. G. Souza Filho, Cláudio A. Perottoni, Francisco Melo, J. Mendes Filho, Waldeci Paraguassu, Marcia Russman Gallas, Jerzy Hanuza, Miroslaw Maczka, Gilberto Dantas Saraiva, and V. Lemos more...
- Subjects
Phase transition ,Chemistry ,Crystal structure ,Triclinic crystal system ,Condensed Matter Physics ,symbols.namesake ,Crystallography ,Phase (matter) ,symbols ,Antiferromagnetism ,General Materials Science ,Raman spectroscopy ,Raman scattering ,Monoclinic crystal system - Abstract
The crystal structure of the paraelastic phase of KFe(MoO4)2 at 360 K was reinvestigated and high pressure Raman scattering experiments were performed on this material. The studies indicated that this molybdate crystallizes in the structure above 312 K. At room temperature the structure is monoclinic and it transforms under pressure into , and low symmetry phases at 0.25, 1.3 and 1.6 GPa, respectively. The phase transitions observed at 0.25 and 1.6 GPa are irreversible whereas the 1.3 GPa transition is reversible. The lattice dynamics calculations performed for the phase allowed us to obtain an assignment of observed modes and helped us to obtain insight into the mechanism driving the structural changes occurring in this material. The x-ray study of the highest pressure phase, recovered during the decompression experiment, shows that the crystal structure of this phase is monoclinic or triclinic. When this phase is subjected to heat treatment at 673 K, it either transforms into another phase or decomposes. more...
- Published
- 2005
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