Principles of a three-dimensional recording model for short wavelength magnetic recording

Principles are provided for a method of evaluating the magnetization of a magnetic recording tape element running in front of a recording gap. The distributions of switching fields P(Hc) and magnetization axes P(θ, φ) used in the calculations are derived from simple experimental results. The output level is calculated by means of the reciprocity principle. The first application of the method concerns certain phenomenological aspects of magnetic recording. As a practical example, a qualitative explanation of the output level curve versus the recording current for short wavelength signals is given; the advantage of microgaps for recording are demonstrated and finally, the circular Bitter patterns discovered by S. Iwasaki are shown to be predicted by the model. This study is a first step toward a more general solution including the demagnetizing field.