Heating and cooling effect of giant magnetoresistive heads during writing operations

Abstract

The temperature change of giant magnetoresistive (GMR) heads is studied at various write frequencies and write currents by measuring the dc resistance of GMR heads during writing operations. To investigate the effect of a disk on the temperature rise, the test was performed at two different conditions: first, head loaded on a disk, and second, head unloaded. There are five kinds of heating sources of spin valve (SV) heads during writings; (1) dc interconnect heating, (2) dc write coil heating, (3) ac interconnect heating, (4) write-to-read cross-talk of interconnect, and (5) ac write coil heating. The primary cause for the temperature rise of the SV head during writing is write-to-read cross-talk of interconnect, when the head is loaded on a disk. When the head is unloaded, dc or ac heating of the write coil is the main cause of temperature rise of the SV head. It was found that a disk plays an important role in the temperature change of GMR heads during writing as a cooling source. The disk hardly reduces the heat generated by read bias current and cross-talk induced current, but it significantly reduces the heat from the dc or ac write coil heating.