Thermal asperity trends

Abstract

A thermo-mechanical model that predicts the changes in thermal asperities as a function of increasing areal density is described. Conceptually, the problem is divided into two portions: the collision and relative motion of an asperity along the slider, and the subsequent diffusion of thermal energy into the head in the vicinity of the read element. The former is treated using a quasi-static spring model for the various mechanical degrees of freedom; the later with a scaling model for the heat transfer. The thermal model was verified by using a focused fast laser pulse to simulate a thermal transient at the read element. The predictions of the full model were also compared with measured thermal asperities that were produced on a spin-stand. The results support one of the model's main predictions: a significant increase in the amplitude of worst case thermal asperity events can be expected in the next few years.