THE STUDY OF THE MAGNETIC MULTIVALUED RECORDING AT THE EXIST OF DIPOLAR INTERACTION

Abstract

A classical method is established to study the conditions for the magnetic multivalued (MMV) recording at the exist of dipolar interaction. In order to simplify the problem, we adopt the approximation that the spins in the same layer have the same direction. With this approximation, a set of nonlinear equations is derived, from which what area of parameters is suitable for the MMV recording can be decided. We use this method to detailedly discuss the two magnetic layers system that can be solved analytically. For this system, the area of parameters, in which the MMV recording can be realized, is presented. We find that a small value of antiferromagnetic coupling between layers will be advantage to MMV recording. And the perpendicular anisotropy must be large enough to overcome the in-plane anisotropy caused by dipolar interaction. We also use the method of spin dynamics to simulate the system. The results show that the theory is applicable.