Gregory S. Mowry

Design Of High Density Dual Stripe MR Heads Using A Thermal Transmission Line Model

A thermal transmission line model is described and used to study the performance of high track density dual stripe magnetoresistive (DSMR) recording heads. The model was calibrated to actual thermal and signal amplitude data by adjusting sensor material properties. Signal sensitivity per unit track width from the preamp are shown to improve by decreasing the sensor thickness. Further improvement with track density is predicted for smaller aspect ratios. For a square active region (aspect ratio =1.0) no degradation in signal sensitivity was seen up to approximately 19 ktpi.

Robust design of a permanent magnet stabilized high areal density magnetoresistive head

As the recording industry increases areal density every year, a magnetoresistive-soft adjacent layer (MR-SAL) head design is desirable with the following qualities: easy to be fabricated in large volume, capable of consistent and stable device-to-device performance, and enough signal to noise ratio to perform at high recording densities and data rates. A new type of MR head with these attributes is described for an areal density equal to 1444 Mb/in.2. The off-track characteristics of this MR head are determined by the sensor edge design which is defined by a permanent magnet (PM) layer. Improved off-track performance was achieved by substituting the spacer layer with the PM outside of the active sensor area. Excellent boundary control stabilization was obtained by the ferromagnetic exchange coupling between the PM and, the SAL and the MR layers. The bit error rate and electrical test results showed acceptable performance at 175 kbpi and 8250 tpi. The above MR head had average values of low frequency ampli...