MAGNETIC-PROPERTIES OF YVO3 FROM SUSCEPTIBILITY AND Y-89 NMR MEASUREMENTS

The magnetic properties of YVO3, a prototype of highly correlated d-el ectron Mott-Hubbard antiferromagnetic (AF) orthovanadates, are studied by means of magnetization and susceptibility measurements, coupled to Y-89 NMR spectra and relaxation. Both field-cooled and zero-field-coo led conditions are considered. The history and field-dependent propert ies recently reported for the AF phases below T-N similar or equal to 113 K and T-N'similar or equal to 77 K are confirmed. The behavior in the paramagnetic phase and around TN is Studied and it is shown how th e field-induced short range order and canted-spin weak ferromagnetism is quenched in strong field, yielding (M/H)(ZFC)similar or equal to(M/ H)(FC) for H similar or equal to 6 T. At variance with the susceptibil ity in strong field, the Y-89 NMR line width shows a divergent behavio r for T-->T-N(+). The Y-89 relaxation rates do not display, for T-->T- N(+), the behavior expected for spin fluctuations of AF-ferromagnetic (FE) symmetry as the one in the ordered state, possibly in view of the quasistatic character of the short range order. (C) 1997 American Ins titute of Physics.