Surface potential imaging for magnetoresistive head development

We demonstrate the first applications of scanning surface potential microscopy to magnetoresistive (MR) thin-film devices. Images are presented on active devices showing 2D maps of the surface potential of energized MR read-head stripes taken from the production line at the puck level. We have found that surface potential line scans (voltage vs. distance) along MR spin valve stripes show slight deviations from linearity, possibly due to nonuniform film magnetization along the length of the stripe.