The physical limits of high density recording in metallic magnetic thin film media

The fundamental physical limits of high density, saturation recording in high hysteresis loop squareness magnetic isotropic metallic media have been investigated based on observations of micromagnetic structure of recorded Co-Re thin films. Study based on the configuration of the "feather-like" ripple structures of the Lorentz TEM image at the transition region and electron deflection shadow image of the surface field configuration of the recorded media indicate that the physical limit of high density recording in the metallic media is the size of magnetic clusters existing in the film. For a Co-10 at % Re film with Hcbetween 200 to 500 oe., thickness of about 50 nm and S* > 90%, the maximum linear packing density the film can provide, as determined from the cluster size, would be less than 25,000 FRPI.