Domain structures in multi-layered Co-Ni-Fe-Pd films observed by spin-polarized SEM

The domain structures of cores with patterned six-layered CoNiFePd films with alumina interlayers are investigated using spin-polarized scanning electron microscopy. The films exhibit virtually single domains in the middle of the magnetic cores with magnetization parallel to the easy axis of the films. Around the pattern edge, the magnetization orients along the pattern edge. At the pole tip, the ratio of the edge domain to the pole width increases as the track width becomes narrow. It is important to prevent the enlargement of such a region so as to maintain the permeability at the pole tip. This domain structure remains stable for different magnetization conditions, a necessary condition for readout waveforms without distortions. Thus the films are suitable for magnetic thin-film heads with narrow track widths