Thermal asperity of TMR heads for removable disk drives

The thermal asperity of the tunneling magnetoresistive (TMR) head was studied using Zip-type flexible media, and compared with that of the anisotropic magnetoresistive (AMR) head. The examined head had a shielded structure with the TMR element close to the air bearing surface. Nevertheless, it generated relatively small thermal asperity even when the mechanical spacing between the head and medium was less than 20 nm, at which large and frequent thermal asperity was observed when the AMR head was used. Such relatively small thermal asperity of the TMR head Is attributed mainly to the small low-temperature coefficient of the electrical resistivity of the TMR element.