A study of GMR read sensor induced by soft ESD using Magnetoresistive Sensitivity Mapping (MSM)
Electrostatic discharge (ESD) can be manifest on giant magnetoresistive (GMR) head either physically (melting of sensor element) or magnetically (degrades in dynamic electrical or quasitest parameters). The latter case is usually suspected as ldquosoftrdquo ESD and known to be a subtle case for study. In this study, we try to differentiate the ldquosoftrdquo ESD from electrical failure, which cause by other means. Ahead with magnetoresistance sensitivity mapping (MSM), which is an additional feature of magnetic force microscope (MFM), the symmetry and sensitivity changes of GMR sensors were further investigated. Advanced analytical tools of atomic force microscope (AFM), MFM and MSM allow unique characterization of head microstructure, and coupled with methodical and systematic failure analysis, may be possible to observe in-situ the previously unknown ESD phenomena unique to GMR head.
Direct measurement of the sensitivity distribution of magnetoresistive heads by the SXM technique
The sensitivity distribution of a magnetoresistive (MR) head was obtained by using a scanning probe microscope (SXM) technique. This technique made it possible to map with submicron resolution the sensitivity distribution on the air-bearing surface of the MR head in relation to the head structure. It was observed that the shape and location of the sensitivity distribution varied with changes in the sense current. Comparison with microtrack measurements showed qualitatively good agreements. >
Fast seismic data compression based on high-efficiency SPIHT
Based on the set positioning in hierarchical tree (SPIHT) algorithm, fast seismic data compression based on the high-efficiency SPIHT (HESPIHT) algorithm is presented. To verify the validity of the algorithm, 10 seismic cross-sections are selected for the experiment. The result shows that the algorithm can reserve the quality of data better, meanwhile improving the efficiency of encoding and decoding.