Scanning Magnetoresistance Microscopy Analysis of Bit Patterned Media Playback

A scanning magnetoresistance microscope (SMRM) was used to enable recording experiments on bit patterned media prototypes not yet suitable for spin-stand evaluation. The SMRM generates a 2D playback response of the media by “dragging” a recording head across the sample using a piezoelectric nanopositioner. A large-scale parameter optimization technique is applied to extract relevant parameters such as pulse amplitude, pulse width, and pulse position from the 2D playback response. The parameters were analyzed to learn that the pulse response of our recording head cannot be accurately modeled as a Gaussian function. The error in the optimized parameters is dominated by intertrack interference and to a lesser extent measurement resolution and thermal drift.