Synthesis, Structure, and Properties of New Perovskite PbVO₃

Abstract

The new perovskite PbVO 3 was synthesized under high-temperature and high-pressure conditions. Its crystal structure (a ) 3.80005(6) Å, c ) 4.6703(1) Å, Z ) 1, S.G. P4mm) contains isolated layers of corner-shared VO 5 pyramids, which are formed instead of octahedra due to a strong tetragonal distortion (c/a ) 1.23). The lead atom is shifted out of the center of the unit cell toward one of two [VO 2 ]-layers due to the influence of the lone pair. This new perovskite exhibits a semiconductor-like F(T) dependence down to 2 K. This behavior can be qualitatively explained by taking into account strong electron correlations in electronic structure calculations.

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

“…Most of the main diffraction lines for the 0.1 MPa pattern can be indexed into a tetragonal structure with a = 3.8091(4)Å, c = 4.6508(13)Å, and V = 67.48(2)Å 3 . The fitted lattice constants are in good agreement with previously presented values for the PbVO 3 T-phase [6,7]. Several other weak peaks are attributed to unknown impurities produced by the complex sample synthesis process.…”

“…The PbVO 3 tetragonal perovskite (P4mm) (T-phase) was synthesized recently at high pressures and suggested to be a candidate multiferroic with a two-dimensional C-type antiferromagnetism (C-AFM) ordering and a large ferroelectric polarization [6][7][8]. The PbVO 3 T-phase is isostructural with PbTiO 3 , but exhibits a more pronounced structural distortion and a much larger unit cell volume.…”

“…The PbVO 3 T-phase is isostructural with PbTiO 3 , but exhibits a more pronounced structural distortion and a much larger unit cell volume. The V 4+ ion in the T-phase deviates markedly from the center of the VO 6 octahedron in the ideal perovskite structure, leading to a much longer V-O1 bond and a very short V-O1 bond along the c-axis. Thus, the PbVO 3 T-phase presents a VO 5 pyramidal rather than a VO 6 octahedral coordination as shown in figure 1(a).…”

“…The V 4+ ion in the T-phase deviates markedly from the center of the VO 6 octahedron in the ideal perovskite structure, leading to a much longer V-O1 bond and a very short V-O1 bond along the c-axis. Thus, the PbVO 3 T-phase presents a VO 5 pyramidal rather than a VO 6 octahedral coordination as shown in figure 1(a). The large distortion manifests as a high c/a ratio of 1.229 and a calculated spontaneous polarization of 152 µC cm −2 [9].…”

Atomic and electronic structures of the SrVO3-LaAlO3 interface

“…Extra electrons have been detected on the interface layer by comparing the energy-loss near-edge structures of V-L 3,2 edges to those from the film far from the interface. Monochromated EELS and theoretical calculations for SrVO 3 , VO 2 , and V 2 O 3 support this conclusion. The extra electrons appear to originate from a change in the local bonding configuration of V at the La-O terminated substrate surface as determined by Z-contrast imaging.…”