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.
Spatial mapping of the sensitivity function of magnetic recording heads using a magnetic force microscope as a local flux applicator
A technique for using a magnetic force microscope (MFM) as a local field source for mapping the sensitivity function of magnetic recording heads is described. The results obtained from applying this technique to both magnetoresistive and inductive recording heads are discussed. >
Greater than 13 Gb/in/sup 2/ spin valve heads
We have designed and fabricated dual spin valve heads with synthetically pinned layers. They have excellent sensitivity. The read-back waveform has a small asymmetry and that is also insensitive to the bias current. The read gap length is of 0.14 /spl mu/m and the write gap length is of 0.2 /spl mu/m. The read heads have a nominal magnetic trackwidth of 0.5 /spl mu/m and a nominal write magnetic trackwidth of 0.8 /spl mu/m. The write heads were conventional inductive heads with their pole geometry defined by focused ion beam (FIB) technology. The dual spin valve heads have achieved an areal read/write density as high as 14.5 Gb/in/sup 2/ at a data transfer rate of 23/spl sim/24 MB/sec. The sensitivity of the readers is as high as 3.6 mVp-p//spl mu/m. The bit aspect ratio is as high as 14.