High-pressure Raman scattering and structural phase transition inYCrO4

Abstract

The high-pressure structural properties of the zircon-type $\mathrm{Y}\mathrm{Cr}{\mathrm{O}}_{4}$ with space group $I{4}_{1}∕amd$ were investigated using Raman scattering techniques in a diamond anvil cell up to $28.9\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ at room temperature. The abrupt changes in Raman spectra indicate that a pressure-induced structural phase transition occurs at a lower pressure $3.0\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, but a wide pressure region up to $15.1\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ is needed to complete this phase transition. Moreover, the high-pressure phase can be quenched at ambient conditions. We calculated the mode Gr\"uneisen parameters and assigned the new phase to be a scheelite-type structure in $I{4}_{1}∕a$ symmetry based on the fact that the Raman spectrum of the new phase is similar to that of the scheelite-type $\mathrm{Y}\mathrm{Cr}{\mathrm{O}}_{4}$ prepared at moderate pressure and temperature conditions. The effects of $3{d}^{1}$ electronic configuration on phase transition pressure and unusual Raman vibrations were discussed.