SrWO₄ at high pressures

Abstract

Room-temperature high-pressure behaviour of SrWO 4 scheelite (I4 1 /a, Z = 4) has been studied to 20.7 GPa in a diamond anvil cell using synchrotron angle-dispersive X-ray powder diffraction. Above 10 GPa, it transforms to the fergusonite structure (I2/a, Z = 4). Both scheelite and fergusonite types are ordered superstructures of fluorite (Fm3m, Z = 4). There is no significant volume collapse at the scheelitefergusonite phase transition. However, the compression data including both phases of strontium tungstate cannot be fitted by a common Birch -Murnaghan equation of state. An onset of decomposition into component oxides occurs at about 15 GPa. The pressure-induced transformations are irreversible.

High-pressure X-ray diffraction study of SrMoO4 and pressure-induced structural changes

“…pressures, unlike what was reported in a previous high-pressure study on SrWO 4 [62]. Hence, the EOS reported above can be assumed as a valid EOS for SrMoO 4 up to 25…”

Compression of scheelite-type SrMoO4 under quasi-hydrostatic conditions: Redefining the high-pressure structural sequence

“…Since phase IV is only observed at two different pressures, we will limit the discussion to mention its possible existence and leaving its characterization to a future work. We would like to add here that evidence of neither amorphization [33][34][35] nor chemical decompositions 36 are detected in our experiments up to 46.1 GPa. Then, probably these phenomena previously reported in scheelite-type oxides could be caused by deviatoric stresses induced in previous experiments.…”

Inelastic neutron scattering studies of phonon spectra, and simulations of pressure-induced amorphization in tungstatesAWO4(A=Ba,Goel1, Gupta2, Mittal3 et al. 2015Phys. Rev. B240140View full textAdd to dashboardCite

“…They also form a part of oxide ceramic composites useful for cryogenic detectors. These possible applications have motivated extensive interest in understanding the fundamental physical properties [20][21][22][23][24][25][26][27][28][29][30][31] of the AWO 4 tungstates.…”

“…These compounds exhibit a rich phase diagram with respect to change in pressure and temperature 23 . Several experimental and theoretical efforts have been undertaken to obtain understanding of the phase diagram of the compounds [20][21][22][23][24][25][26][27] , which still remains elusive. Extensive Raman 27,28,29 and infrared 30 scattering techniques have been used to study the zone centre phonon modes in several of these tungstates.…”