A simplified model of high density tape recording

A simplified vector field model is used to analyze isolated pulse asymmetry, input/output curves, nonlinearities in dibit recording, and overwrite for thick longitudinal tape. The recording layer of a well oriented medium is discretized into laminae, and the magnetization transition parameter and phase in each lamina are determined by both the vector head field and vector demagnetizing field. Typical head-medium spacing is considered as well as imaging of the demagnetizing fields by the record head. A significant magnetization transition phase shift and an increasing transition length with depth into the media are produced by the demagnetizing field, which plays a central role in explaining the phenomena of high density tape recording. Both pulse asymmetry and nonlinearities increase with demagnetizing ratio 4πM_r/H _c. The signal voltage increases with bit length and decreases with the demagnetizing field in agreement with experiment. Overwrite for fixed frequency improves for larger deep gap field until the head field to coercivity ratio H_g/H_c reaches 3.5 and then subsequently decreases, for typical head-medium spacing d/g=0.25 and 4πM_r/H_c=2. 2F/1F overwrite maximizes when the bit length of the 2 F signal equals the gap length in agreement with measurement