Playback pulse shape and spectra for shielded MR heads

Simple analytical expressions for the longitudinal surface fields from four types of shielded magnetoresistive (MR) heads, i.e., single element MR heads (both centered and off-center), dual-stripe heads, and 'differential' MR heads are derived using superposition and Schwarz-Christoffel transformation. These expressions are utilized to study playback pulse shape and spectra. For the centered shielded MR head as well as the dual stripe shielded MR head, simple accurate formulas for [PW.sub.50] and [D.sub.50] are derived. For the dual stripe MR head, the model predicts the position of the first spectral gap null accurately, as well as the voltage spectral shape.