The Effect of Hydrostatic Pressure on the Magnetic Anisotropy of Ferrous and Ferric Ions in Ferrites with Spinel Structure

抄録

The first order magnetic anisotropy constant K₁ of eight ferrites with inverse-type spinel structure and two ferrites with normal-type has been measured under hydrostatic pressure by the use of a torque method. The pressure dependence of K₁, K₁⁻¹(dK₁⁄dp), in Li_0.5Fe_2.5O₄ is +4.1×10⁻⁶ bar⁻¹, in NiFe₂O₄ is +3.3×10⁻⁶ bar⁻¹, in Li_0.05Fe_2.95O₄ is −18.0×10⁻⁶ bar⁻¹, in Fe₃O₄ is −13.5×10⁻⁶ bar⁻¹, in Fe_2.96Ti_0.04O₄ is −9.4×10⁻⁶ bar⁻¹, in Fe_2.90Ti_0.10O₄ is −6.5×10⁻⁶ bar⁻¹, in Fe_2.82Ti_0.18O₄ is −1.4×10⁻⁶ bar⁻¹, in Fe_2.69Ti_0.31O₄ is +3.0×10⁻⁶ bar⁻¹, in MnFe₂O₄ is +7.0×10⁻⁶ bar⁻¹, in Mn_0.8Zn_0.2Fe₂O₄ is +6.0×10⁻⁶ bar⁻¹ at room temperature. The results are discussed with regard to a single-ion model. In spinel, the contribution of ferrous ion to anisotropy constant K₁ increases, and that of ferric ion decreases, with decreasing lattice constant under hydrostatic pressure.