Theory of magnetic small-angle neutron scattering of two-phase ferromagnets

Article

关键词: EXCHANGE-STIFFNESS CONSTANT;    SPIN DISORDER;    SATURATION;    ALLOYS;    MICROSTRUCTURE;    VITROPERM;    COLLOIDS;    IRON;   

DOI  :  10.1103/PhysRevB.87.224426

来源: SCIE

【 摘 要 】

Based on micromagnetic theory, we have derived analytical expressions for the magnetic small-angle neutron scattering (SANS) cross section of a two-phase particle-matrix-type ferromagnet. The approach-valid close to magnetic saturation-provides access to several features of the spin structure, such as perturbing magnetic anisotropy and magnetostatic fields. Depending on the applied magnetic field and on the magnitude H-p of the magnetic anisotropy field relative to the magnitude Delta M of the jump in the longitudinal magnetization at the particle-matrix interface, we observe a variety of angular anisotropies in the magnetic SANS cross section. In particular, the model explains the clover-leaf-shaped angular anisotropy, which was previously observed for several nanostructured magnetic materials, and provides access to the magnetic interaction parameters, such as the average exchange-stiffness constant. It is also shown that the ratio H-p/Delta M decisively determines the asymptotic power-law exponent and the range of spin-misalignment correlations.

【 授权许可】

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