MAGNETIZATION REVERSAL MECHANISMS AND TIME-DEPENDENT PROCESSES IN THIN TB FE MULTILAYER FILMS/

In this paper we apply the interpretation of magnetization measurement s developed in an associated paper to Tb/Fe multilayers for magneto-op tic recording applications. Our results show that remanence curves and delta-/ plots are able to determine the controlling mechanism for mag netization reversal in Tb/Fe multilayers. In the multilayer with the g reatest Tb content this domain nucleation controlled magnetization rev ersal gave way to domain wall pinning controlled reversal for films wi th more than 6 bilayers. In the intermediate Tb content multilayers, d omain wall pinning became important only after 20 bilayers, whereas fo r the lowest Tb content film reversal remained domain nucleation contr olled throughout the series. The form of the time dependence of magnet ization is connected to the magnetization reversal process. All the fi lms that showed magnetization reversal dominated by domain nucleation also exhibited a nonlinear ln(t) time dependence whereas films showing domain wall pinning reversal exhibited a linear ln(t) time dependence . The form of the activation volume as a function of applied field is the same for all the films controlled by domain nucleation processes.