Characterization of Slider Dynamics and Media Defects by Concurrent Methods Using Multifunctional Spinstand

As areal density increases towards Tb/in², disk media defect detection becomes more critical. We have developed a media tester for concurrent multifunctional testing and mapping. A special test sample with defect features of various depths and sizes was fabricated by focused ion beam, and studied on the tester by concurrent magnetic read-back envelope measurement (ME) and laser Doppler vibrometry (LDV) mapping. The ME approach was found superior in detection sensitivity and resolution than LDV and shown to be useful for indirect detection of media surface physical variations. Besides defect characterization, ME mapping provided two-dimensional information on slider-surface interaction. However, correlation with other concurrent tests such as LDV and acoustic emission (AE) must be done, to eliminate spurious results. A concurrent mapping of AE, LDV, ME, and in situ flying height on media defects was also performed, and the excitation of different slider modes by different surface defects was observed in situ. Such concurrent testing is important towards providing an ldquoaccurate picturerdquo of the tested media surface and slider flying condition.