Magnetic and transport properties of CeVO 3

Abstract

Magnetic data are presented that indicate the VO 3 array of the perovskite CeVO 3 exhibits the same anomalous properties as in LaVO 3, including (1) a first-order magnetostrictive distortion below a T t < T N, (2) a canted-spin ferromagnetism below T N, (3) a reversal of the direction of the vanadium atomic moments on traversing T t, and (4) suppression of T t in an isostructural metastable phase prepared under hydrostatic pressure. The VCe exchange field operating at the Ce 3+ : 4 f 1 configurations below T N does not change sign on traversing T t. The Ce-atom magnetization reduces the field for nucleation of irreversible magnetization processes; both La 0.5Ce 0.5VO 3 and CeVO 3 exhibit MH hysteresis loops characteristic of hard ferromagnets, whereas the magnetization of LaVO 3 remains reversible in fields H = ±50 kOe. For x ≥ 0.25, substitution of Sr for Ce in Ce 1- x Sr x VO 3 does not create small-polaron V 4+ ions, but delocalized V-3 d states and an intermediate Ce 4+/Ce 3+ valence at the Ce atoms. Strong correlations among the itinerant V-π∗ electrons of stoichiometric, metallic SrVO 3 reintroduce long-range magnetic order at low temperatures.