Structural properties of the zircon- and scheelite-type phases ofYVO4at high pressure

The laser host material yttrium orthovanadate ${\mathrm{YVO}}_{4}$ with a tetragonal zircon-type structure has been studied by angle-dispersive powder x-ray diffraction in a diamond anvil cell up to $26\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ $(T=300\phantom{\rule{0.3em}{0ex}}\mathrm{K})$. In situ diffraction confirms that the compound undergoes a nonreversible transformation to a scheelite-type structure at a pressure of $8.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The equations of state of the zircon and scheelite phases and changes in internal structural parameters are reported. The effect of pressure on the distorted tetrahedral and dodecahedral coordinations of the V and Y ions, respectively, is discussed.