4-4 材料的磁学性能 magnetic properties of materialsWhat are magnetic field strength. magnetization, flux density, permeability and magnetic susceptibility?Two sources of magnetic moments in materials.The nature and source of diamagnetism,paramagnetism and ferromagnetismDomain and magnetic hysteresis; why ferromagnetic and ferrimagnetic materials experience magnetic hysteresis;Soft and hard magnetic materials.4-4 材料的磁学性能 (magnetic properties)4-4-1 物质的磁性1、磁学基本量（1）磁矩表征磁性物体磁性大小的物理量。m电子轨道磁矩电子自旋磁矩物体本身特性方向：右
