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 H
k
may be determined. The H
k
values deduced from the different methods are discussed especially with respect to their dependence upon the magnetization ripple and on distinct
H_{c}/H_{k}
ratios. Although some of the reviewed methods yield H
k
values not influenced by the ripple hysteresis, only the planar Hall effect method and the modified Kobelev method enable rapid measurements or continuous recording of H
k
. These methods are, therefore, found to be especially suitable for measurements of the H
k
relaxation during annealing experiments.