MAGNETIC RECORDING MEDIUM

摘要

PURPOSE: To make it difficult to simultaneously rewrite magnetic information and to effectively prevent forgery by including >=2 kinds of magnetic materials which vary in coercive force but are nearly the same in initial magnetization curves in magnetic recording layers. CONSTITUTION: The magnetic materials of the first magnetic recording layer 3a and the magnetic material of the second magnetic recording layer 3b vary in the coercive force and, therefore, the saturation writing currents of the first magnetic recording layer 3a and the second magnetic recording layer 3b eventually vary when the magnetic recording layers 3 are subjected to writing and once attain a magnetization state. Then, the simultaneous rewriting of the first magnetic recording layer 3a and the second magnetic recording layer 3b is difficult and the rewriting of only the magnetic recording layer having the low coercive force is possible. Accordingly, the information illicitly written on the magnetic recording layer of the low coercive force and the intrinsic information recorded on the magnetic recording layer of the high coercive force eventually coexist and the reading out of the information is infeasible. The forgery is thus easily discriminated.