Magnetic disk device having piezoelectric element

A magnetic disk device comprising:

• a magnetic disk configured to rotate around a first axis;
• a gimbal that includes a magnetic head configured to perform recording and reproducing of data with respect to the magnetic disk, and a piezoelectric element configured to be deformed in accordance with an applied drive voltage to move the magnetic head;
• a controller configured to apply a polarization voltage to the piezoelectric element to give spontaneous polarization to the piezoelectric element;
• an actuator configured to rotate around a second axis to move the magnetic head with respect to the magnetic disk;
• a ramp distant from the first axis in a first direction around the second axis, and configured to hold the actuator;
• and
• a stopper configured to be brought into contact with the actuator to restrict the actuator from rotating in a second direction opposite to the first direction,
• wherein the polarization voltage satisfies a relationship of ΔV=(2πf)A·ΔT<ΔVmax, where “ΔV” is a voltage change amount of the polarization voltage per unit time, “f” is a frequency of the polarization voltage, “A” is an amplitude of the polarization voltage, “ΔT” is a time resolution of the polarization voltage, and “ΔVmax” is a voltage change amount per unit time that excites resonance of the gimbal in application to the piezoelectric element, and
• the controller is configured to apply the polarization voltage to the piezoelectric element when the actuator is in contact with the stopper.