Recording characteristics and thermal stability comparisons between antiferromagnetically coupled and conventional media (invited)

We report on the recording performance and thermal stability of antiferromagnetically coupled (AFC) media with varying top and bottom layer thickness as compared with those of highly oriented conventional longitudinal recording media. AFC media offers the expected merit of low M(r)t designs such as narrow pulse width (PW50), while maintaining good thermal stability. However, the magnetostatic field resulting from thicker total magnetic thickness in AFC media results in poor overwrite (OW) and a degradation in nonlinear transition shifts (NLTS). Thermal stability of AFC media is mainly determined by intrinsic coercivity of the top layer plus the AF exchange field and the magnetostatic field acting on the top layer through a Ru layer. Low noise conventional media with high orientation ratio (OR) can be produced with an acceptable thermal decay equivalent to AFC media at M(r)t values above 0.25 memu/cm(2). (C) 2002 American Institute of Physics.