Investigation of the phase stability of LuVO₄at high pressure using powder x-ray diffraction measurements and lattice dynamical calculations

Abstract

High pressure angle dispersive x-ray diffraction measurements are carried out on LuVO 4 in a diamond anvil cell up to 33 GPa at the Elettra synchrotron radiation source. The measurements show that LuVO 4 undergoes a zircon to scheelite structure phase transition with a volume change of about 11% at about 8 GPa. A second transition to a monoclinic fergusonite structure occurs above 16 GPa. The data are also recorded while releasing the pressure, and indicate that the scheelite phase is metastable under ambient conditions. The equations of state and changes in internal structural parameters are reported for various phases of LuVO 4 . Lattice dynamical calculations based on a transferable interatomic potential were also performed and the results support the stability of the scheelite structure at high pressures. The calculated structure, equation of state and bulk modulus for all the phases are in fair agreement with the experimental observations.

High-pressure powder x-ray diffraction study of EuVO4

“…4 that follows it as pressure changes. Similar changes have been observed in HP x-ray diffraction studies on other rare-earth orthovanadates [7,14,41]. These changes are consistent with a transformation from the scheelite-type structure to a monoclinic fergusonite-type structure as previously observed at a similar pressure in EuVO 4 [7].…”

Equation of state and electronic properties of EuVO4: A high-pressure experimental and computational study

“…A larger peak width is typical for rare-earth-orthovanadate scheelite phase under compression (broad reflections of the highpressure scheelite-type phase have been frequently observed for other scheelite orthovanadates under pressure, e.g. for YVO 4 [45] and LuVO 4 [12]), and it is attributed to the small crystallite size of the scheelite phase. This pressure-driven phase transition at room temperature is illustrated Table 1 for the earlier literature data on the transition point.…”

“…[10]. At higher pressures, a fergusonite-type phase has been reported for EuVO 4 [11] and for some other members of the RVO 4 family (e.g., LuVO 4 [12]). …”

In situhigh-pressure synchrotron x-ray diffraction study of CeVO4and TbVO4up to 50 GPa

“…During the last decade, intensive investigations have been carried out on the structural evolution of the zircon-type vanadates under extreme conditions. In particular, x-ray diffraction [3 -6], optical [7,8], and Raman scattering measurements [4,6,8,9,10], and theoretical calculations [5,6,10,11] have been carried out to understand the structural modifications induced by pressure. Orthovanadates with small A cations have been observed to undergo an irreversible zircon-to-scheelite (space group: I4 1 /a, Z = 4) phase transition [3].…”