Voltage pulsing for localized clearance measurement

Reliable measurement techniques are important to determine the clearance for a given head/disk interface. In this paper a new localized approach is introduced for the measurement of the clearance between slider and disk. A voltage pulse of 50 μs duration is applied to the head/disk interface, resulting in a reduction of the slider/disk spacing due to the attractive force between the charged slider and the disk. The magnitude of the voltage pulse can be increased in small increments until slider/disk contact occurs. A simultaneous measurement of the slider displacement due to the voltage pulse determines the clearance change.