Magnetic properties of Ce3+ in Pb1-xCexSe: Kondo and crystal-field effect

Electron paramagnetic resonance (EPR) experiments were performed on a Pb1-xCexSe crystal at liquid-helium temperatures and show very clearly that the doublet Gamma(7) is the ground state for cerium ions. The cubic symmetry is shown and the effective Lande factor for the Ce3+ is determined to be 1.354+/-0.003. An orbital reduction factor is introduced to explain the g experimental value. High-field magnetization results are in good agreement with the EPR results. The nominal Ce composition in PbSe deduced from saturation of the magnetization, x = 0.0405 +/- 0.0003, is very closed to the Value determined by microprobe analysis (x = 0.04). At 1.5 K, an antiferromagnetic interaction between the nearest-neighbor cerium atoms is found, J(ex)/k(B) = -0.715 K. The low-field magnetic-susceptibility results show that the magnetic moment of cerium impurities is strongly temperature dependent, explained by the presence of the crystal-held effect and the Kondo effect.