THEORETICAL EXPLANATION OF SPIN REORIENTATION IN DyTiFe₁₁ COMPOUND

At room temperature, the c-axis is the easy magnetization direction in DyTi Fe₁₁ compound. However, when we decrease temperature, the thermal magnetic curves show that a spin reorientation takes place at about 175K. The anisotropy constants of Fe sublattice have been determined by measuring the magnetocrystalline anisotropy of YTi Fe₁₁. We have calculated the anisotropy constants of Dy by using single ion theory. The results demonstrate that the spin reorientation arises from the competition of magnetocrystalline anisotropy between Dy and Fe sublattices. The spin reorientation is explaned by the theoretical calculation.