HEAD-MEDIUM CONTACT DETECTION USING AN OSCILLATING ELECTROMAGNETIC FORCE

摘要

An apparatus comprises circuitry configured to apply an AC signal having a frequency to one of a slider of a recording head and a magnetic recording medium. The applied AC signal causes an oscillation in an electrostatic force and clearance between the slider and the medium at the frequency of the AC signal. A thermal sensor is configured to generate a sensor signal at the AC signal frequency in response to sensing changes in temperature resulting from the oscillating clearance. A detector is coupled to the circuitry and the thermal sensor. The detector is configured to detect one or both of head-medium spacing changes and head-medium contact using a phase of a first harmonic or an amplitude of a second harmonic of the thermal sensor signal.

主权项

1. A method, comprising:
applying an AC signal having a frequency to one of a slider of a recording head and a magnetic recording medium, the AC signal causing an oscillation in an electrostatic force between the slider and the medium at the frequency of the AC signal; causing, by the oscillating electrostatic force, an oscillation in a signal produced by a thermal sensor at the slider, the thermal sensor signal oscillating at the AC signal frequency; and detecting one or both of head-medium spacing changes and head-medium contact using a phase of a first harmonic or an amplitude of a second harmonic of the thermal sensor signal.