About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
IEEE Transactions on Magnetics
Paper
Thermal proximity imaging of hard-disk substrates
Abstract
We discuss a new measurement technique called thermal proximity sensing (TPS) and its application to the inspection of magnetic hard-disk surfaces. This method uses the magneto-resistive (MR) readback element of a hard-disk file in a novel thermally sensitive mode to actively sense the air-bearing gap spacing while the disk spins under the slider. We present model calculations that describe the origin of the thermal sensitivity and its range of applicability. By collecting height information as a function of position, we have obtained high-resolution images of disk topography with sensitivity in the subnanometer range. Initial results of the technique, obtained on a test stand, showed an exceptional imaging ability for surface features. We have also obtained useful surface structure data from in situ measurements of disk surface defects in an operating hard-disk file.