Structural properties of PbVO₃perovskites under hydrostatic pressure conditions up to 10.6 GPa

Abstract

High-pressure synchrotron x-ray powder diffraction experiments were performed on PbVO 3 tetragonal perovskite in a diamond anvil cell under hydrostatic pressures of up to 10.6 GPa at room temperature. The compression behavior of the PbVO 3 tetragonal phase is highly anisotropic, with the c-axis being the soft direction. A reversible tetragonal to cubic perovskite structural phase transition was observed between 2.7 and 6.4 GPa in compression and below 2.2 GPa in decompression. This transition was accompanied by a large volume collapse of 10.6% at 2.7 GPa, which was mainly due to electronic structural changes of the V 4+ ion. The polar pyramidal coordination of the V 4+ ion in the tetragonal phase changed to an isotropic octahedral coordination in the cubic phase. Fitting the observed P-V data using the Birch-Murnaghan equation of state with a fixed K 0 of 4 yielded a bulk modulus K 0 = 61(2) GPa and a volume V 0 = 67.4(1)Å 3 for the tetragonal phase, and the values of K 0 = 155(3) GPa and V 0 = 58.67(4)Å 3 for the cubic phase. The first-principles calculated results were in good agreement with our experiments.

Emergence of a Cubic Phase Stabilized by Intermetallic Charge Transfer in (1 – x)PbVO3–xBiCoO3 Solid Solutions

“…On the other hand, the cubic phase (high-pressure phase) should be quenched in 0.25PbVO 3 –0.75BiCoO 3 . PbVO 3 and BiCoO 3 underwent paraelectric phase transition, turning into a cubic Pm 3̅ m structure for PbVO 3 and an orthorhombic Pnma structure for BiCoO 3 , around a high pressure of ∼3 GPa. − The large volume difference resulted in the remaining quenched metastable cubic phase even at atmospheric pressure, indicating that the cubic phase was stabilized. The cubic phase fraction decreased because of an annealing effect that led to the release of the inner stress of the sample.…”

Intermetallic Charge Transfer in V-Substituted PbCrO3

“…Since 27 Pb positions cannot be divided by 2, this ordering structure is not long-ranged but short-ranged. Such a distribution of Pb 2+ and Pb 4+ is therefore called the charge glass state. , As observed in BiNiO 3 , PbCrO 3 shows a pressure-induced CT between Pb and Cr accompanied by a discontinuous 9.8% volume shrinkage at 2.5 GPa. , Accordingly, a chemical substitution for Cr in PbCrO 3 is expected to enable a CT upon heating at AP leading to a cubic-to-cubic transition and a colossal NTE.…”

Colossal Negative Thermal Expansion in Electron‐Doped PbVO3 Perovskites

“…The 3d 1 electronic configuration enlarges the pyramidal distortion. PbVO 3 exhibits a colossal volume collapse accompanying the ferroelectric‐to‐paraelectric transition at high pressure (HP, about 3 GPa) . The magnitude of the intrinsic volume contraction reaches about 10 %.…”