PW50, D-50, and playback voltage formulas for shielded magnetoresistive heads

Simple, approximate formulas for PW50, D-50, and peak playback voltage for shielded magnetoresistive (MR) heads are developed using the Potter approximation for the MR surface potential and the tanh model for the medium transition. The results can be utilized to analyze the role of parameter variation on signal voltage. The PW50 expression agrees well, for all practical magnetic spacings, with the Fourier series method which solves for the accurate MR surface potential. The product PW50D50 is nearly a constant 1.45. The calculated curve of peak voltage versus PW50 is compared with experimental data and good agreement is obtained. (C) 1997 American Institute of Physics.