Anisotropy Dispersion of Amorphous Co-Metal Films

The effect of heat treatment on the anisotropy dispersion of CoZr films was studied. To induce anisotropy, film samples were annealed using a rotating field (RFA) and a direct field (DFA). The sum of the anisotropy field and the demagnetizing field of the DFA film (11.5 Oe) corresponded well with the value of the magnetic field of the distribution peak. The DFA ¿Q half value of less than ±10° indicates a well aligned anisotropy, but the anisotropy of RFA films was dispersed in all directions. The initial anisotropy of these RFA films did not sufficiently relax under the annealing conditions, but prolonging RFA increases the peak width and dispersion and may decrease the macroanisotropy. The anisotropy dispersion of CoFeB and CoTi films is about the same.