Temperature-dependent magnetic properties of : Effective spin Hamiltonian modelO. N. Mryasov, U. Nowak, K. Y. Guslienko and R. W. Chantrell
Seagate Research - 1251 Waterfront Place, Pittsburgh, PA 15222, USA
received 8 November 2004; accepted 22 December 2004
published online 9 February 2005
A model of magnetic interactions in the ordered ferromagnetic is proposed on the basis of first-principles calculations of non-collinear magnetic configurations and shown to be capable of explaining recent measurements of magnetic-anisotropy energy (MAE). The site (,) resolved contributions to the MAE have been distinguished with small easy-plane and large easy-axis terms. This model has been tested against available experimental data on the temperature dependence of MAE showing scaling of uniaxial MAE (K1(T)) with magnetization (M(T)) characterized by the unusual exponent of . It is shown that this unusual behavior of the can be quantitatively explained within the proposed model and originates from an effective anisotropic exchange mediated by the induced moment. The latter is expected to be a common feature of 3d-5d(4d) alloys having 5d/4d elements with large spin-orbit coupling and exchange-enhanced Stoner susceptibility.
75.30.Gw - Magnetic anisotropy.
75.50.Ss - Magnetic recording materials.
71.15.Rf - Relativistic effects.
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