Study of shield effect on magnetoresistive head performance using magnetoresistive sensitivity map and spin-stand tester

The effect of the bottom shield on magnetoresistive (MR) head read-back per formance was systematically studied by using a spin-stand tester and a magn etic force microscope with magnetoresistive sensitivity map (MSM) capabilit y. Two groups of high density MR heads with identical design, processes and materials, except for their bottom shields, were tested. It was found that the higher the initial permeability of the shield, the smaller the PW50, t he steeper the 50% height slope and the smaller the shoulder in the corresp onding side of the isolated transition read-back pulse. The MSM images and analysis not only corroborated the spin stand results, but they also gave a dditional information about the isolated pulse shape and cross-track profil e. The MSM was found to be a useful tool in studying the shield effects on isolated pulses as well as their impact on microtrack profiles. (C) 2000 Am erican Institute of Physics. [S0021-8979(00)87708-7].