Influence of head fields and media properties on transitions of magnetization reversals on thin film disk.

Abstract

This paper describes a relationship between transition lengths and head fields with media of various coercivities. The transition lengths were written by a single sided and a double sided MIG head on three thin film media which have the coercivity of 874, 1121 and 1270 Oe. The transition lengths were surveyed through the colloid SEM observation. The head fields of the MIG heads were analyzed by the finite-element method (FEM) with magnetic saturation taken into account. The following phenomena were found. First, the 2nd fields stray from saturated ferrite region near the interface between a metal film and ferrite core of the MIG head. Second, the transition lengths are spread by the influence of the 2nd field when the strength of the 2nd fild is higher than a half of the media coercivity. On the other hand, if the media coercivity is two-times higher than the 2nd field strength, the transition length is strongly related to the field gradient of the primary field at the recording zones.