Modeling and experimental investigation of thermal interaction in the head-disk interface of mr head based recording systems

Abstract

I Intmduetion The read-back signal thermally induced from the head-disk interface is one of the most serious concern in the engineering integration of the MR head based rewrding systems. especially when technology moves to sub-micro-inch beaddisk spacing and 40 Gb/in2 mal densities [l][2]. This paper presents the results of thermal signal modehng, beating and cooling process simulation, and experimental analysis. An analytical model is proposed which takes the headdisk spacing into account and can be used for quantitative analysis of the head-disk systems. Results of the transient process study show that a submicron lateral resolution c m be achieved for characterizing the disk surface. Experimental inveslipations, supported by the analytical model, indicate thhd the air thermal conductivity inside the laser bump hole is smaller than that of outside the bump hole. Satisfyiog agreement between estimated bump shape and the bump shape measured by AFM is achieved when proper thermal conductiviv ratio is used. Experimental results also suggest that the MR thermal signal can be used for in-situ monitoring of the headdisk spacing variation, with the relationship provided by the proposed analytical model.