Magnetic Anisotropy

Abstract

A crystal with a certain crystal structure is anisotropic. Therefore, the free energy of a magnetic crystal depends on the direction of the spontaneous magnetization vector $$\vec {M}_\mathrm{ s}$$ with respect to the lattice axes. The anisotropy is called magnetocrystalline anisotropy. The magnetostatic energy of a non-spherical magnetic body also depends on the $$\vec {M}_\mathrm{ s} $$ direction. The anisotropy is called Shape anisotropy. Additional magnetic anisotropy may be induced through some treatment in some magnetic media. Such anisotropy is called induced magnetic anisotropy. Magnetic atoms in amorphous alloys have magnetic anisotropies with randomly distibuted easy‐axis directions. Such anisotropy is called random anisotropy. This chapter introduces typical phenomena and basic theories of the anisotropies.