The anisotropy field Hkof thin ferromagnetic films, measured by magnetoresistive methods

Several methods are described based on the magnetoresistance and the planar Hall effect by which the anisotropy field strength Hkmay be determined. The Hkvalues deduced from the different methods are discussed especially with respect to their dependence upon the magnetization ripple and on distinct ratios. Although some of the reviewed methods yield Hkvalues not influenced by the ripple hysteresis, only the planar Hall effect method and the modified Kobelev method enable rapid measurements or continuous recording of Hk. These methods are, therefore, found to be especially suitable for measurements of the Hkrelaxation during annealing experiments.