Magnetization reversal mechanisms and time-dependent processes in Tb-Fe-Co alloy films

In this paper we develop an interpretation of magnetization data appropriate to materials where magnetization reversal occurs as a two-stage process: domain nucleation followed by domain wall motion, and apply it to films with perpendicular magnetic anisotropy. An interpretation of remanence curve data and time dependence data for a two-stage reversal system is proposed. The two principal remanence curves (IRM and DCD) yield data on the energy barrier distribution, while the delta-I plot which compares these two remanence curves offers a method of characterizing the relative importance of domain nucleation and domain wall motion. The interpretation is then applied to a series of Tb22Fe70Co8 magneto-optic thin films where the film thickness varies from 164 to 830 Å. All but the thickest film show magnetization reversal is controlled by both domain nucleation and domain wall motion. In the 830 Å film only domain wall motion appears important in controlling reversal.