CRYSTAL FIELDS IN THE VALENCE-UNSTABLE CENI-BASED COMPOUND

The influence of a partial delocalization of cerium 4f electrons on th e crystalline electric field (CEF) effects measured on Pr paramagnetic impurity ions have been investigated for the series of (Pr, Ce)(x)(La , Y)(1-x)Ni compounds, which undergo the transition from the intermedi ate valence (IV) to Kondo state due to the chemical substitution. In t he Kondo state the hybridization of cerium 4f electrons and conduction electrons results only in the simultaneous increase of all CEF parame ters, while in the IV regime the partial delocalization of cerium 4f e lectrons is responsible for a charge redistribution that manifests its elf in different scales of changes for different CEF parameters.