Study of overwritten magnetization at the off-track position

Overwritten magnetization at the off-track position is studied by using micro-magnetic simulation employing the Landau-Lifshitz-Gilbert equation. The nominal track width was 600 nm and bit length was 100 nm. The first bit of overwritten magnetization at large off-track distances more than 50 nm is connected with the third bit at high frequencies. This is due to the decrease of the head field at the edge. The magnetization of the track edge is not quite reversed after completing overwrite. As the frequency increases, the head field decreases due to rise-time effects, so that overwrite cannot be completed normally. An increase in the resistivity of the head core material is useful in order to improve the off-track overwrite characteristics.