Active Flying-height Control of Magnetic Head Slider using MEMS Thermal Actuator

Abstract

Today's head/disk interface design has a wide flying height distribution due to manufacturing tolerances, environmental variations, and write-induced thermal protrusion. To reduce the magnetic spacing loss due to these effects, we have developed an active head slider with nano-thermal actuator. The magnetic spacing of these sliders can be controlled in-situ during operation of the drive. After simulating the heat transfer in the slider and resulting thermal deformation of the air-bearing surface, we fabricated a thermal actuator by thin film processing. The evaluation by a read/write tester showed a linear reduction in magnetic height as electric power was applied to the actuator. The actuator's stroke was 2.5 nm per 50 mW with time constant of 1 msec. We found no significant impact to the reliability of the read element.