Data erasure apparatus and data erasure method

A data erasure apparatus for a data storage device which includes a magnetic disk to record data, a motor to rotate the magnetic disk and a base to which the motor is fixed, in which said data erasure apparatus erases data in said data storage device while the magnetic disk is rotating, said data erasure apparatus comprising:

• an external magnetic field generating section which is faced toward one side of the magnetic disk and generates an external magnetic field to erase data recorded on the magnetic disk externally of the data storage device;
• and
• a magnetic substance which is located on an opposite side of the magnetic disk so as to face the motor outside the data storage device and generates a magnetic force which acts on the motor in an opposite direction of a magnetic force of the external magnetic field,
• wherein the magnetic substance has a cylindrical shape, and the surface of the magnetic substance facing to the motor has a circular shape.

A data erasure method for erasing the data of a data storage device which includes a magnetic disk to record data, a fluid dynamic bearing motor to rotate the magnetic disk and a base to which the fluid dynamic bearing motor is fixed, said data erasure method comprising:

• generating an external magnetic field to erase data recorded on the magnetic disk;
• rotating the magnetic disk in the external magnetic field to erase data recorded on the magnetic disk by a magnetic force of the external magnetic field;
• and
• generating a magnetic field outside the data storage device by moving a magnetic substance having a rotational axis aligned with a rotational axis of the motor, in a direction of the rotational axis of the motor, so that a magnetic force acts on a rotating rotor of the fluid dynamic bearing motor in an opposite direction of the magnetic force of the external magnetic field so as to retain the rotation of the rotor.