In this article, we present a study on the micromagnetics of exchange biased Permalloy films. Specifically, by combining magnetic force microscopy with micromagnetic modeling simulation, the magnetization reversal processes in exchange biased Permalloy films were studied. The bilayer films were lithographically patterned into micrometer scale rectangular elements. It is shown that the micromagnetic simulations accurately predict domain configurations during magnetization reversal of the exchange biased Permalloy film elements and provide detailed magnetization distributions and transient dynamic magnetization configurations that could not yet be obtained experimentally. The study found that, for both NiO/NiFe and FeMn/NiFe systems, the exchange bias field measured on individual patterned micrometer scale bilayer film elements can be significantly larger than that measured on the sheet film sample.

Quantitative interpretation of a magnetic force microscopy (MFM) image usually requires detailed knowledge of the magnetization configuration of the sensing tip. Here, we demonstrated a technique that converts the obtained raw MFM image into the magnetic pole density distribution without explicitly knowing the tip magnetization orientation. By creating an approximate point source of magnetic poles in the same sample imaged, the impulse response function of the MFM tip is obtained for deconvolution of a raw image in the Fourier space. Experimental demonstrations with various tip magnetization orientations were performed on recorded magnetic transitions in a thin film longitudinal medium.

A potential approach to extending current thin film media to 100 Gbits/in2 recording density is physical patterning of the media, perhaps via an etching technique. An advantage of patterning is the capability of creating advanced position error signal (PES) patterns that are difficult or impossible to generate with writing by a recording head. This study uses spin stand tester to investigate various PES patterns generated by a focused ion beam etching technique on conventional thin film disks. For all practical purposes, the patterned PES eliminates transition noise, track edge noise, and erase band, therefore, demonstrates a much better PES signal than conventionally written servo patterns.

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