MAGNETIC AND TRANSPORT-PROPERTIES OF CEVO3

Magnetic data are presented that indicate the VO3 array of the perovsk ite CeVO3 exhibits the same anomalous properties as in LaVO3, includin g (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 directio n of the vanadium atomic moments on traversing T-t, and (4) suppressio n of T-t in an isostructural metastable phase prepared under hydrostat ic pressure. The V-Ce exchange field operating at the Ce3+:4f(1) confi gurations below T-N does not change sign on traversing T-t. The Ce-ato m magnetization reduces the field for nucleation of irreversible magne tization processes; both La0.5Ce0.5VO3 and CeVO3 exhibit M-H hysteresi s loops characteristic of hard ferromagnets, whereas the magnetization of LaVO3 remains reversible in fields H = +/-50 kOe. For x greater th an 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 int ermediate Ce4+/Ce3+ valence at the Ce atoms. Strong correlations among the itinerant V-pi electrons of stoichiometric, metallic SrVO3 reint roduce long-range magnetic order at low temperatures. (C) 1995 Academi c Press, Inc.