Stress-induced g shifts of r, levels for rare- earth ions.

Abstract

The angular dependence of stress-induced shifts of the gyromagnetic factor g of the r, doublets of Yh3+ and Dy in CaF and Er in CeO, and ThO have been measured in electron-paramagnetic-resonance experiments. The observed variation of the angular dependence of the g shifts is explained in terms o f a phenomenological spin-lattice Hamiltonian. A microscopic theory is used to obtain a quantitative evaluation of the observed shifts using a point-charge model for the induced crvstalline field. The results indicate that covalent effects and the shielding of the electric field at the impurity site are important.