The effect of write head structures on written transitions in perpendicular media

To increase the linear recording density in perpendicular media there are at least two issues, which should be addressed. The first is reduction of transition curvature, this can reduce the amplitude of the output signal and limit the linear recording density. A crescent-shaped main pole head has been proposed as one way to reduce transition-curvature. A second, related problem is how to increase the head-field gradient in the down-track direction. Higher head-field gradients allow sharper transitions to be written and delay the onset of percolation between written bits. One way to increase the head field gradient is to place a trailing shield behind the main pole. In this paper we make a detailed investigation of crescent-shaped main-pole heads and compare their recording performance with rectangular main-pole heads and heads with trailing shields.