ELECTRON-PARAMAGNETIC-RESONANCE SPECTRUM OF PR4+ IN BACEO3

The electron paramagnetic resonance spectrum of a powder of Pr4+ in BaCeO3 was measured at 8.5 K. A very large hyperfine interaction with the Pr-141 nucleus was observed. In addition to the allowed hyperfine transitions, forbidden hyperfine transitions were observed. The results were analyzed based on the weak field approximation, i.e., Breit-Rabi formula, and the g value, \g\ 0.745(1) and the hyperfine coupling constant, \A\ = 0.0606(2) cm(-1), were obtained. From the measured g value, the Gamma(7) --> Gamma(8) crystal field transition for BaPrO3 obtained from an earlier inelastic neutron scattering experiment, and setting the spin-orbit coupling constant to its free ion value zeta = 865 cm(-1), the energy levels of pr(4+) in BaCeO3 were calculated. The measured magnetic susceptibility of BaPrO3 was compared to the values calculated with the above model. (C) 1994 Academic Press, Inc.