DISK STORAGE DEVICE, WRITING CONTROLLER, AND WRITING CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To improve a bit error rate of data recorded using a magnetic head provided with an STO.SOLUTION: A disk storage device according to the present embodiment comprises: a magnetic head; a determination unit; and a controller. The magnetic head includes a high frequency assist element arranged near a main magnetic pole generating a recording magnetic field for performing vertical magnetic recording on the magnetic disk in response to an input recording signal. During data recording, the magnetic head applies a high frequency magnetic field from the high frequency assist element onto the magnetic disk. The determination unit determines whether a recording density of the recording signal is a low density region or a high density region relative to a reference density at certain intervals. The controller relatively lowers a current level for applying a current to the high frequency assist element from the high density region at timing of the low density region in accordance with the low density region or the high density region during the data recording.