The effect of the switching rate dependence of coercivity on recording performance

Abstract

A technique was developed to determine the dynamic remanent coercivity, Hc,r, of the writing process using a spin stand to measure the fundamental signal harmonic as a function of write current. The technique also provides a measurement of the remanent-moment-thickness product, Mrt, as well as coercive squareness, S*. These measurements were compared with measurements done with a Kerr-effect magnetometer for various media having different alloy compositions and/or processing conditions. It was found that recording parametrics such as PW50 and media jitter correlated well with the dynamic coercivity at actual recording field switching rates. Measurements of adjacent track interference or “squeeze” were also found to have excellent correlation with the dynamic media coercivity.