Analysis of magnetic recording fields

THE PROBLEM of magnetic recording has been approached in several ways in the published literature.¹‾⁷ However, none of these works has considered in detail the nonlinearity of the magnetic properties of the coating and the implications of this nonlinearity in recording. Thus, some of the work has been based on oversimplifications of the actual problem, making precise and accurate conclusions unlikely. For instance, under the common simplifying assumption that the medium has a relative permeability of unity (or any other constant value) it is easy to lose sight of the following facts: