Magnetic anisotropy in (HoxEr1-x)2Fe14B pseudoternary intermetallic compounds

The magnetocrystalline anisotropy and the magnetic phase diagram of the pseudoternary (ErxHo1-x)2Fe14B were studied by using the singular point detection technique, thermomagnetic analysis, low-field AC and DC susceptibility and polar dependence of Mparallel and Mperpendicular to measurements. The competition among the different anisotropic contributions gives rise to a complex magnetic phase diagram in which a complete axis-cone-plane spin-reorientation transition is observed with decreasing temperature for x>0.6. A linear composition dependence of the anisotropy was found in the temperature range 200-293 K, which constitutes an indication of the single-ion origin for the anisotropy in these compounds. A microscopic single-ion crystal electric mean-field model has been used in order to explain the origin of the spontaneous spin-reorientation transitions as well as the thermal dependence of the measured anisotropy fields for all concentrations.