Micromagnetic structures of track-center and track-edge transitions recording in thin film media with a thin film head

Future rigid disk magnetic recording systems require heads with both narrower track widths and lower flying heights. As the recorded track width decreases, side writing and reading effects have a more significant affect on the performance of a system. Lower flying heights will affect the micromagnetic structures of the magnetization transitions at not only the center of the track but also at the edge of the track. Both of these effects will have a significant affect on the signal and noise characteristics of a system. The magnetic structure of recorded transitions have been investigated by several techniques including Bitter colloid technique, Lorentz transmission electron microscopy (TEM), spin-polarized scanning electron microscopy with polarization analysis (SEMPA), and magnetic force microscopy (MFM). Lorentz microscopy was used to study the sawtooth or zig-zag wall structures and magnetic vortices at the center of recorded transitions and the micromagnetic structures near track edges of tracks. The purpose of this paper is to describe a new technique for obtaining clearer micromagnetic structures of track-center and track-edge transitions recorded in high-coercivity thin film media with a thin film head by superimposing the sharp "bright lines" of over-focused and under-focused Lorentz Fresnel TEM images of the same transition.