A method of ultra-high resolution magnetic imaging in situ to the drive has been developed. Enhanced magnetization images are produced through deconvolution of the linearized readback by a synthesized two-dimensional head response kernel. The technique first linearizes the measured output by removing the nonlinear GMR head transfer curve. In situ deconvolved images are correlated with conventional MFM (scanning probe-tip) images. After deconvolution, one can readily obtain two-dimensional images with sub-30 nm resolution.

The effect of texturing on the readback signal of Co-alloy thin-film disks is investigated. Instantaneous pulse area (PA) traces, representative of the magnetic signal strength, and instantaneous pulse width (PW,,) traces, indicative of the transition resolution, are measured. The low-frequency, "twice-around" modulation is removed from these traces. The resulting PA fluctuations are small; the PW fluctuations are larger and closely correlated to the texture. Calibration of PW vs flying height allows comparison of the texture-induced head clearance modulation and the actual disk surface roughness. The texture causes signal resolution (PW) noise which, for these head/disk combinations? is predominantly due to the spacing loss variations during the readback process. The write process and any texture-related H, or it-i/ fluctuations appear to contribute negligibly.

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Zn Situ media lubricant thickness in a hard disk drive is measured by analysis of amplitude modulation (AM) in the readback signal. Amplitude modulation is mapped over an area of the disk and the image is scaled into equivalent spacing loss using the Wallace spacing loss equation. The first image is used as a reference for subsequent measurements. Head to disk spacing is modified by the removal of a section of lubricant from a small portion of the imaged region. The area is re-imaged and subtracted from the reference. The new image shows the resulting changes in head/disk spacing. The change in lubricant thickness after either a Freon TF or TF ethanol wash was between 0.6 nm and 0.7 nm.