Electron paramagnetic resonance spectra of Pr4+ in BaCeO3, BaZrO3, BaSnO3, and their solid solutions

The electron paramagnetic resonance (EPR) spectra of powders with Pr4+ doped in BaCeO3, BaZrO3, BaSnO3, and their solid solutions were measured at 4.2 K. A very large hyperfine interaction with the Pr-141 nucleus was observed. The results were analyzed based on the weak held approximation, i.e., the Breit-Rabi formula, and the g values and hyperfine coupling constants A were obtained. The measured g values are much smaller than \-1.429\, which shows that the crystal field effect on the behavior of a 4f electron is large. The value of \g\ decreases from 0.741 (Pr4+/BaCeO3) to 0.583 (Pr4+/BaSnO3), and is caused by the increase of the crystal field due to the shrinking of the lattice. On the other hand, the hyperfine coupling constants are almost constant: A = 0.060(1) cm(-1). (C) 1996 Academic Press, Inc.