Analytic 3-D read head model with finite shields

This paper presents an analytic model of a read head with shields of finite length and width, suitable for replay at 1 Tb/[in.sup.2]. The model determines the shield potential by iterative solution of the equations governing the Fourier coefficients, given an initial guess. The model is used to demonstrate the effect of varying the length and width of the shields. The paper gives results for the shield potential, equipotentials, vertical head field, and spectral response function. A head with shields that are the same length as the semi-shield--shield gap offers an almost constant magnitude response over a broad range of along-track frequencies, and the use of sufficiently wide side shields is advantageous. Index Terms--Digital recording, frequency response, magnetic recording/reading heads, perpendicular recording, 3-D response.