Magnetization creep in magnetic films

Magnetization reversal in planar magnetic films can occur for field amplitudes well below the static threshold. Repeated field transitions parallel to a film´s hard axis in the presence of an easy-axis field can cause slow motion or creeping of the domain boundaries. Experimental observations of magnetization creep and proposed creep mechanisms are reviewed. Creep was studied in slow-rising sinewave and pulsed hard-axis fields. The effective creep thresholds obtained for these cases are compared. In an operating mode in which a bipolar easy-axis pulse and a unipolar word pulse are used, creep is reduced and the effective creep threshold is improved. Examples of domain growth in unipolar and bipolar hard-axis fields are shown in a series of Kerr optical photographs demonstrating the creep process.