System and method for measuring absolute transducer-medium clearance using a thermal response of an mr transducer

An apparatus for measuring absolute clearance between a slider and a medium moving relative to the slider, the apparatus comprising:

• a magnetoresistive (MR) transducer comprising an MR element and supported by the slider, the MR transducer producing a signal that varies as a function of clearance between the MR element and the medium, the signal comprising a thermal component representing a thermal response of the MR element;
• a controller that controls a velocity of the medium relative to the slider, the controller reducing the velocity of the medium relative to the slider;
• and
• a processor, coupled to the controller and MR transducer, that computes a rate of change of the signal during reduction of the medium-slider velocity and determines a medium-slider threshold velocity at which the rate of change of the signal exceeds a pre-established threshold, the processor determining, for a nominal medium-slider velocity, absolute clearance between the slider and the medium using the threshold velocity and a clearance profile associated with the slider.

A data storage system, comprising:

• a data storage disk mounted to a motor;
• at least one magnetoresistive (MR) transducer comprising an MR element, the MR transducer supported by a slider and producing a signal that varies as a function of clearance between the slider and the disk, the signal comprising a thermal component representing a thermal response of the MR element;
• a movable support structure, the support structure supporting the slider and moving slider across the disk;
• a controller, coupled to the motor, that controls a velocity of the disk relative to the slider, the controller reducing the velocity of the disk relative to the slider;
• and
• a processor, coupled to the controller and MR transducer, that computes a rate of change of the signal during reduction of the disk-slider velocity and determines a disk-slider transition velocity at which the rate of change of the signal exceeds a pre-established threshold, the processor determining, for a nominal disk-slider velocity, absolute clearance between the slider and the disk using the transition velocity and a clearance profile associated with the slider.