Magnetic erasures due to impact induced interfacial heating and magnetostriction

High-velocity intermittent contacts between a slider and a disk may lead to data erasure dice to interfacial heating and high-speed mechanical contact stresses. These potential modes of erasure are investigated by artificially introducing high contact stresses that are nor likely to be observed in disk drives. Nevertheless, the mechanisms of erasure are delineated in this study with little ambiguity by comparing the results from three different substrate materials, namely Al-Mg, glass, and Si. We show that written flux patterns can be erased if either the substrate material has low thermal conductivity or if the magnetic layer is damaged. We conclude that if the disk is not plastically damaged by high-speed contacts, then the magnetostriction effect or stress-induced erasure is insignificant. In this case, the dominant factor in erasure is a rise in the interfacial temperature, which is exacerbated by low thermal conductivity of the substrate.