Abstract
The magnetic after effect constant (Sv), the distribution of the anisotropy field (HA), and the rotational hysteresis integral (Rh) were measured for M-type hexagonal strontium ferrite (SrM) fine particles having various average particle diameter (D) and coercive force (HcJ). The relationships between Sv, the activation volume (v), HcJ, HA, and Rh were studied, as well as the milling effects. Sv is constant and independent of the magnetic field. ln Sv vary in proportion to ln HcJ, and the relation HcJ∝v-2 is obtained in SrM particles which were subjected to less milling effect. Sv increases and v decreases for SrM fine particles (D=0.3μm) whose HA is widely distributed by milling, even though HcJ decreases markedly. Sv and v are related to the distribution of HA. As HcJ increases, Rh and v decreases, which in dicates that magnetization reversalmechanism of SrM line particles approaches to that of the coherent rotation mode.
