Investigation of Crystal Field in PrNi₅

Abstract

Recently intermetallic compounds of RNi₅ type have been of interest to many research groups in connection with the application of LaNi₅ based alloys in hydrogen technology (storage, purification of hydrogen, catalysis)¹. One of the main features in most of the intermetallic compounds of the rare earth metals is the splitting of ground state multiplet of the rare earth ion by the interaction with the crystalline electric field (CEF). The number of levels and their degeneracy is determined by the symmetry of CEF which depends on the crystal structure, but a concrete level position and overall splitting depends on the form of electrical potential in metal. So CEF contains the direct information about the electronic structure of the material. In particular, one can study the effects of hydrogen absorption on the electrical potentials by investigating how absorbed hydrogen effects the CEF levels (in particular the ground state multiplet). In this connection a knowledge of CEF seems important to our understanding of the electronic structure of LaNi₅.