Heat Assisted Magnetic Recording With Laser Pulsing

In conventional heat assisted magnetic recording, a thermal write assist is provided by a near field transducer which is constantly energized by a laser during writing. Here, we report experimental and theoretical data where the laser is pulsed, whereby the pulsing can be synchronous or asynchronous to the write clock. It is found that the recording performance of pulsed heat assisted recording is slightly deteriorated when compared with conventional dc operation. This is explained by the combined effect of an increased magnetic-to-thermal offset and fast freezing dynamics. The deterioration of the recording performance can be eliminated by an increase of pulsing frequency so that the inherent low-pass behavior of the thermal response of the medium removes the temperature variations that occur in the recording layer.