Guiding principle for research on perpendicular magnetic recording

Complementarity law between contrastive characteristics of longitudinal and perpendicular recording is described. Significant dependence of recording resolution upon media parameters of recording layer (thickness δ, coercive force H_c, and remanence induction B_s) in longitudinal recording is indicated. In contrast, the parameters do not govern the resolution in perpendicular recoding. This essential difference is caused by the opposite effects of demagnetization. Read/write characteristics in drives are found to obey the complementarity during prototyping.