磁层介质在记录讯号后,其内部产生一个与讯号磁化强度方向相反的退磁场,导致磁层中讯号磁化强度的减小,甚至破坏,这就是退磁效应。它是纵向磁记录提高记录密度的重大障碍。在数字式纵向磁记录的情况下,由记录讯号本身产生的退磁场,使得磁层上相邻磁化区域之间,磁化强度的改变不是阶 Magnetism media in the recording signal, its internal and signal magnetization direction opposite to produce a demagnetizing field, resulting in the magnetization signal in the magnetic layer to reduce or even destroy, which is the demagnetization effect. It is a major obstacle to longitudinal recording to improve recording density. In the case of digital longitudinal magnetic recording, the demagnetizing field generated by the recording signal itself is such that the change in the magnetization between adjacent magnetized regions on the magnetic layer is not a step