THE MAGNETISM OF RARE-EARTH INTERMETALLICS USING COMPUTER ALGEBRA - APPLICATION TO PRAL2 AND NDAL2

The magnetism of rare-earth intermetallic compounds is investigated wi th a model Hamiltonian containing crystal field and exchange terms. An algebraic analysis of the characteristic polynomial associated with t he model is made and it is shown that, for Pr3+ (J = 4) and Nd3+ (J = 9/2), in the case of cubic symmetry, the ninth- and tenth-degree polyn omials are decomposed into simple factors. From these factors, analyti cal expressions for the crystal field eigenvalues, the magnetic moment s and the critical temperatures are derived. The results are applied t o PrAl2 and NdAl2; exchange parameters and effective g factors are eas ily obtained from crystal field, T(C) and low-temperature magnetic mom ents data.