Anomalous behavior of the magnetic entropy in PrNi5

By considering a Hamiltonian that includes the crystalline electric field a nd exchange interaction components we showed theoretically that paramagneti c PrNi5 exhibits an anomalous entropy behavior in which the magnetic entrop y increases with increasing magnetic field at low temperature. This anomaly in magnetic entropy can be fully understood and is associated with the cro ssing of the two lowest magnetic energy levels (Gamma(4) and Gamma(1)). Exp erimental verification of the anomalous behavior of the magnetic entropy in polycrystalline PrNi5 was obtained. [S0163-1829 (98)02045-1].