Narrow-track antisymmetric dual magnetoresistive head performance on rigid media

In this work, the performance of an antisymmetric dual magnetoresistive (A-DMR) head, having a track-width of W_t=2 μm, a stripe height of h=2 μm and a gap length of 80 nm, is presented and compared to theory. A thin film inductive head that incorporates high magnetization FeAlN poles, with a gap length of 0.25 μm, was used to record thin film disk media with an areal magnetic moment of 0.5 memu/cm² and a coercivity of 3 kOe. The A-DMR roll-off and spectral curves that are fit in amplitude and shape with a 2-D analytical curve, indicated D50=190 kfci. The theoretical curves fit the experimental data with two fitting parameters, the spacing parameter of the spacing loss term and a parameter ζ=ζ (W_t/h) that can be calculated with a 3-D micromagnetic model. The cross-track profile, off-track response and adjacent track interference are analyzed in the time domain and compared with previously reported theoretical results, where in this case the write head track-width is 2.5 μm. The head showed some adjacent track interference and pulse amplitude asymmetry at lower linear densities, mainly due to a lower magnetic transverse bias level of one of the sensor layers. In spite of the good linear resolution of these heads, they offer limited sensitivity in comparison to spin valve heads