Effect of Shape on the Bias Field of an Ni-Fe/Ti/Co-Zr-Mo Trilayer MR Element

The effect of shape on the bias field of an Ni-Fe/Ti/Co-Zr-Mo trilayer MR element is discussed in relation to the aim of controlling the bias field of MR heads. In the case of a single-layer Ni-Fe film, the field at half-maximum MR coefficient was found to be proportional to the thickness and the reciprocal of the height. In the case of a trilayer MR element, the saturation bias field was proportional to the Co-Zr-Mo thickness. The bias field was saturated at smaller sense currents, and the saturation bias field increased as the Ti thickness was decreased. The use of a Co-Zr-Mo surface oxidation layer instead of a Ti layer in the trilayer MR element was effective, because it was possible to fabricate the element as a uniform thin film.