A System for Head Disk Contact Studies Using Contact Thermal Signals

Publishing Venue

IBM

Abstract

Disclosed is a system for head disk contact studies using contact thermal signals. This system includes the following components: 1. An environmental chamber with a pressure range of 1.0-0.01 atm. 2. A spin stand assembled inside the environmental chamber. 3. Electronic channels and software for thermal contact signal detection.

A System for Head Disk Contact Studies Using Contact Thermal Signals

   Disclosed is a system for head disk contact studies using contact thermal signals. This system includes the following components:

1. An environmental chamber with a pressure range of 1.0-0.01 atm.

2. A spin stand assembled inside the environmental chamber.

3. Electronic channels and software for thermal contact signal detection.

     The detected thermal signal of this system is due to the electric resistance change induced by temperature change of MR/GMR sensors when they are in contact with disks after lowering the pressure. Figure 1 shows a typical waveform of the contact thermal signal. The negative polarity of the signal indicates that the MR/GMR sensor's temperature decreases. This is because the Joul heat generated by the sensor's bias current is absorbed by the disk lubricant layer, disks films, and substrate via thermal conduction. The contact thermal signal has been used to determine the head disk contact and lift off pressure. The amplitude and frequency of the contact thermal signal can be used to study the slider vibration frequency, disk take off height, and thermal conducting properties of disk lubricant layers, disk films, and substrates.

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Fig.1 A typical contact thermal signal waveform.

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