Single-Pole Heads with Thin Fe-Si Main-Pole Films

The linear recording density in perpendicular magnetic recording is limited by the thickness of the main-pole in the single-pole head. In order to raise the practical readback resolution, a thin main-pole film is indispensable. Fe-Si film has a large saturation magnetization and good soft magnetic properties are obtained at thicknesses between 50 and 200 nm. However, as the film thickness decreases below 100 nm, the domain wall structure and domain configuration change from Bloch-type walls and closure domains. A head with such a thin film as its main-pole has unstable readback output and poor resolution. The authors therefore adopted as the main-pole an Fe-Si/SiO2 multi-layered film whose domain structure differs from that of a single-layer Fe-Si film. As a result, the output stability and high-density response could be improved by controlling the intermediate layer (hereafter "inter-layer") thickness and the number of magnetic layers.