SINGLE-ION COMPETING MAGNETIC ANISOTROPIES IN PRXND1-XCO5 INTERMETALLIC COMPOUNDS

Competing single-ion 4f magnetic anisotropies have been studied within a noncollinear three-sublattice mean-field crystal-electric-field model in order to explain the observed complex magnetic behavior in the pseudobinary series PrxNd1-xCo5. The interplay of different magnetic anisotropies gives rise to a contribution in the spontaneous free energy which turns out to have a minimum for the direction of the magnetization along a non-major-symmetry direction. A comparison with the experimental data of the spin-reorientation temperature and also with the thermal evolution of the spontaneous-spin-reorientation angle has allowed the determination of a reliable set of crystalline-electric-field parameters for the Pr3+ and Nd3+ ions. A calculation of the theoretical magnetization isotherms has been undertaken using these crystalline-electric-field parameters, in order to determine the theoretical magnetic anisotropy field, which has been compared for different temperatures and concentrations with experimental results obtained from singular-point-detection measurements.