Dependence of spontaneous magnetization and constants of magnetic anisotropy on the size of nanocrystals

A hypothetical ferromagnetic with a simple cubic structure is used as an example for considering from a microscopic standpoint one of the causes of lower spontaneous magnetization (connected with the form factor) in small crystals as compared to macrocrystals. An algorithm is suggested for determining the constants of magnetic anisotropy on the basis of the dipole-dipole interaction of the effective magnetic moments of atoms in the crystals with allowance for their symmetry. The effective magnetization by this mechanism can vary from a low value to a large one corresponding to macrocrystals depending on the demagnetization factor of the particles.