Large Pressure Effects on the Magnetic Phase Diagrams of CeSb and Ce_x(La_0.76Y_0.24)_1−xSb Compounds

Abstract

Cerium and uranium monopnictides of rocksalt structure, exhibit unusual and very anisotropic magnetic properties compared to the other rare earth or actinide compounds^l. This behavior is attributed to the proximity of the 4f (or 5f) level and the Fermi level. To explain this trend, Cooper et al.² have proposed an interaction between the f electrons via the d electrons of the rare earth, whereas Takegahara, Yanase and Kasuya³ have suggested a strong hybridization between the f electrons of the rare earth and the p electrons of the valence band. This f-p hybridization, normally smaller than the f-d one, is enhanced by the proximity of pnictide and cerium atoms and by the existence of p-holes in the valence band due to the semimetallic character of these compounds³⁻⁶. CeN,which is metallic, is considered as non-magnetic. The complexity of the magnetic properties increases with the semimetallic character in the cerium monopnictides series from CeN to CeBi. A strong exchange anisotropy due to multiphase behavior arises for CeSb and CeBi and in contrast with the other rare earth monopnictides, the splitting Δ between the ground state and the excited state is unusually small^7,8.