DISK DEVICE AND DATA ERASING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a disk device which can effectively erase data on a magnetic disk while suppressing the operation of a magnetic field on a spindle motor. SOLUTION: The top cover 14 of the disk device is provided with pole pieces 14a1 and 14a2. When this disk device is placed in an external magnetic field, a magnetic field which is local and has a steeper magnetic gradient than the external magnetic field is produced from the pole pieces 14a1 and 14a2. When the pole pieces 14a1 and 14a2 are arranged on the inner peripheral side of the magnetic disk, data on the magnetic disk can effectively be erased while the operation of the magnetic field on the spindle motor is suppressed.