THE INFLUENCE OF CRYSTAL ELECTRICAL-FIELD ON FIRST-ORDER AND SECOND-ORDER MAGNETIC PHASE-TRANSITION IN PRASEODYMIUM INTERMETALLICS

In order to investigate the influence of crystal electrical field on d etermining the first- or second-order ferromagnetic-paramagnetic phase transition, we have considered Praseodymium intermetallics systems Pr X2 (X = Al,Ni,Rh,Ru,Mg), Using a theoretical model which takes into ac count the crystal field and exchange interaction, we have studied in a nalytical form the Landau free energy as a function of the model param eters, that leads to a phase diagram, which permits to show that the e xistence of first- or second-order magnetic phase transitions is stron gly related to the magnitude of crystal field and critical temperature . (C) 1998 Elsevier Science B.V. All rights reserved.