MIG Head Identifying that Metal Film Runs Parallel to the Gap Forming Layer

Various metal-in-gap (MIG) heads have been developed for use in high-density recording systems. We report on a MIG head composed of a Mn-Zn ferrite core and sputtered FeGaSiRuO metal film, and in which the metal film is shown to run parallel to the gap-forming layer. In this type of head, the boundary between the metal and the ferrite usually acts as a pseudo-gap, resulting in a ripple in the playback output spectrum. It was found experimentally that some metal elements and oxygen, contained in both the magnetic metal alloy and the ferrite, diffuse around the boundary during the heating process. Due to the diffusion of these elements, nonmagnetic and weakly magnetic layers grow at the boundary and form a pseudo-gap. We suppressed the formation of these undesired layers by using FeGaSiRuO alloy with a high Bs, thus remarkably reducing the ripple in the playback output spectrum.