MAGNETIC-ANISOTROPY IN (ERXHO1-X)2FE14B PSEUDOTERNARY INTERMETALLIC COMPOUNDS

The magnetocrystalline anisotropy and the magnetic phase diagram of th e pseudoternary (ErxHo1-x)2Fe14B were studied by using the singular po int detection technique, thermomagnetic analysis, low-field Ac and DC susceptibility and polar dependence of M(parallel-to) and M(perpendicu lar-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 w ith decreasing temperature for x > 0.6. A linear composition dependenc e of the anisotropy was found in the temperature range 200-293 K, whic h constitutes an indication of the single-ion origin for the anisotrop y in these compounds. A microscopic single-ion crystal electric mean-f ield model has been used in order to explain the origin of the spontan eous spin-reorientation transitions as well as the thermal dependence of the measured anisotropy fields for all concentrations.