Patent ID: 9607642
Date: 2017-03-28
CPC Classifications: G11B

Claim:
1. A method, comprising: applying an AC signal having a specified frequency and a DC offset voltage to one of a substrate of a slider and a magnetic recording medium, a low- or non-modulation interface defined between the slider and the medium; causing, in response to applying the AC signal, an oscillation in an electrostatic force between the slider and the medium at the specified frequency; 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 specified frequency; adjusting a heater of the slider to decrease a spacing between the slider and the medium during oscillation of the electrostatic force; for each heater adjustment, measuring a resistance of the thermal sensor over a specified number of medium revolutions; and detecting head-medium contact using one of an amplitude of a harmonic of the thermal sensor signal and a summation of amplitudes of all frequency components at the specified frequency.