Spatial correlation between magnetic force microscope images and recording head output

We have developed a technique which directly compares magnetic force microscope (MFM) images and recording head read-back signals on longitudinal thin-film disks with exact spatial correlation. To get exact spatial correlation we had to perform three important operations at the same position on the disk. We wrote data with an inductive recording head; we read-back the data with the same head; and we imaged the data with an MFM. Using this technique we show that MFM images are related directly to the read-back signal. As one of the examples of this technique, we saw a signal anomaly which could have been mistaken for media noise which from the MFM image was proven to be incomplete overwrite.