Characteristics of Metal Magnetic Thin Film in MIG Head and Head Performance

A MIG head, with metal magnetic thin film in the gap, has been developed for use with high-coercivity media. But the head has problems with a pseudo-output caused by a pseudo-gap at the interface between the Fe-Al-Si alloy thin film and the ferrite, and low R/W efficiency. The pseudo-gap is caused by a damaged layer of ferrite by mirror lapping in the ferrite and the initial layer of the Fe-Al-Si film, which is about 0.1 μm thick and has a relative permeability of 10. The result of examinations of the magnetic properties of the initial layer indicates that this layer causes the pseudo-output. These problems are solved by inserting Ni-Fe intermediate thin film between the Fe-Al-Si film and the ferrite, which lowers the coercive force of the Fe-Al-Si thin film and significantly reduces the pseudo-output.