MAGNETIC AND TRANSPORT-PROPERTIES OF CEVO3

Magnetic data are presented that indicate the VO3 array of the perovskite CeVO3 exhibits the same anomalous properties as in LaVO3, 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 Ce3+:4f(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 La0.5Ce0.5VO3 and CeVO3 exhibit M-H hysteresis loops characteristic of hard ferromagnets, whereas the magnetization of LaVO3 remains reversible in fields H = +/-50 kOe. For x greater than or equal to 0.25, substitution of Sr for Ce in Ce1-xSrxVO3 does not create small-polaron V4+ ions, but delocalized V-3d states and an intermediate Ce4+/Ce3+ valence at the Ce atoms. Strong correlations among the itinerant V-pi* electrons of stoichiometric, metallic SrVO3 reintroduce long-range magnetic order at low temperatures. (C) 1995 Academic Press, Inc.