Write field gradient effect on perpendicular recording

An effect of the write field gradient on perpendicular recording has been studied by three-dimensional finite-element method and micromagnetic modeling. Two conceptual writer designs were compared: the conventional trailing pole (TP) writer with the main pole serving as the trailing pole and the leading pole (LP) writer, where the main pole operates as the leading pole. Both writers record transitions on double-layer media by the trailing edge of the main pole. The LP writer allows effective control of the write field gradient by positioning the trailing edge adjacent to the write gap. The dependencies of the perpendicular H-PERP and longitudinal H-LONG components of the write field along with a gradient of the perpendicular component H-PERP/dx and write angle on write gap length g and write current I-W were computed. The LP writer revealed higher H-PERP/dx than the TP writer at gless than or equal to2 mum. The H-PERP/dx has a maximum at I-W=15-20 mA for both writers and decreases with the current increase. The LP writer exhibited higher H-PERP/dx and write angle Theta, as well weaker dependence of these parameters on write current than the TP writer in all ranges of current. Micromagnetic modeling of recorded patterns has shown that the LP writer provides better writeability, and a sharper and less curved transition. Both writers demonstrated the best performance at I-W=15-20 mA where H-PERP/dx and the write angle have the maximum. Severe transition distortion was observed for the TP writer at I-W>30 mA. (C) 2003 American Institute of Physics.