GlobusモデルによるMnZnフェライトの磁区構造解析  [in Japanese] Analysis of the Domain Structures of MnZm Ferrites Using Globus'Model  [in Japanese]

Globus'Model was used to investigate the domain structures of MnZn ferrites. The model assumes that the energy losses during a cycle in the expression of the hysteresis loop have two origins: the continuous pinning of the domain wall and the formation and destrucion of a fraction of the wall surface. In the case of MnZn ferrites, the pinning force is proved to be negligible, and the wall energy derived from this model shares a temperature dependence with hysteresis losses. Although Globus'model postulates that a grain includes only one domain wall, our experimental results for samples with various average grain diameters indicate that at room temperature, grains with an average diamere of more than 8μm would include more than two unit cells in which one domain wall moves. At higher temperatures, the difference in cell sizes becomes smaller as the magnetocrystalline enegy K_1 approaches zero.