On recording head field theory

Several well-known theoretical treatments of the properties of the fringing field from a magnetic recording head are shown to yield a non-zero dc flux response, which is physically impossible. This deficiency is due to the approximations in the models rather than mathematical error. Plausible long wavelength spectra may be derived from better models, but they are usually of great mathematical or computational difficulty. In this paper, a simple approximation is suggested which yields correctly the qualitative features of the whole spectrum. In conclusion, the topical case of narrow pole-tip-length heads is discussed.