磁気と磁性第9回強磁性体の磁化過程とヒステリシス

摘要

Hysteresis phenomena in the magnetization process of ferromagnets are discussed.After characteristics of the hysteresis loops in the M-H plane are explained, the Gibbs free energy of single magnetic domain particles with the uniaxial symmetry is formulated. On the basis of an analysis of the local minima of the free energy, the change in the magnetization under a varying magnetic field, i.e., the formation process of a hysteresis loop is discussed.Relaxation phenomena such as magnetic after-effects and the coercivity of magnetic fine particles are discussed including the possibility of utilizing the particles as recording media for memory devices.