Tutorial on magnetic recording theory

In this talk, the more fundamental issues confronting magnetic recording theory will be reviewed in a fashion which should be of interest to both recording specialists and other magneticians. The absence of a usable, microscopic, vector model of the recording medium magnetization is the principal theoretical problem in both recording and other magnetic studies. M‐H curve fitting or, better, the Preisach function approach1 yields only limited information on the recorded signal and none on the medium noise. In contrast, the theory of recording head fringing fields appears to be nearly complete; recent results on narrow pole‐tip heads2 and on pole‐tip partial saturation effects3 will be reviewed. After a brief discussion of theory of the anhysteretic4 and thermo‐remanent processes, some results of large scale modeling5 of the write process will be presented. A salient finding of these experiments is a rotating vector magnetization pattern which may not be understood fully without a vector M‐H presciption; th...