Magnetization Contrast Enhancement of Recorded Magnetic Storage Media in Scanning Lorentz Electron Microscopy

An imaging technique suitable for observing bit patterns on longitudinal media using a scanning Lorentz electron microscope has been investigated. In regularly recorded media, the effect of magnetization on the image contrast tends to be reduced by stray magnetic field. It is shown, however, that the magnetization contribution to the contrast can be enhanced compared to the stray field contribution when the sample is tilted in a specific direction. A numerical estimate shows that 60° tilting about an axis along the track direction should give a net contrast which is four times greater than with no tilting. This contrast enhancement upon tilting the sample has been confirmed through the observation of recorded CoPt media.