External bit field analyses

Three-dimensional external bit fields emanating from single and multiple magnetic transitions with a finite track width have been calculated. The magnetic field interferences between tracks have been also simulated. The results show that the fields have a large component in the track width direction near the transition edges. This contributes to field extension in the neighboring track direction. The amount of extension decreases with bit density increase. The results of our calculations are backed up by Lorentz microscopy observation of films in which bit fields are transcribed.