In situ x-ray diffraction and Raman spectroscopy of pressure-induced phase transformation in spinel Zn2TiO4
Abstract
In situ x-ray diffraction and Raman spectroscopy were used to explore the pressure-induced phase transformation of spinel Zn2TiO4 to pressures of 52.4 and 81.1 GPa, respectively. Results indicate that spinel Zn2TiO4 initially transforms to the orthorhombic (CaTi2O4) structure at 23.7 GPa, and such a phase transition is complete at 32.4 GPa. This high-pressure phase has a bulk modulus of 205 (6) GPa, higher than that of the cubic spinel phase [162 (11) GPa], and at extrapolated to one atmosphere is 2.1% denser than the spinel phase. Upon phase transformation, we observed two additional Raman modes assigned to the newly formed high-pressure phase, whereas the six proceeding Raman modes of the spinel phase disappeared. Upon release of pressure to ambient conditions, the CaTi2O4 phase transforms to a tetragonal polymorph, in which the two observed Raman modes differ in pressure shifts from those of the CaTi2O4 polymorph.
- Publication:
-
Physical Review B
- Pub Date:
- June 2002
- DOI:
- 10.1103/PhysRevB.66.024103
- Bibcode:
- 2002PhRvB..66b4103W
- Keywords:
-
- 62.50.+p;
- 81.40.Vw;
- High-pressure and shock wave effects in solids and liquids;
- Pressure treatment