A PZT microactuator such as for a hard disk drive has a restraining layer bonded on its side that is opposite the side on which the PZT is mounted. The restraining layer comprises a stiff and resilient material such as stainless steel. The restraining layer can cover most or all of the top of the PZT, with an electrical connection being made to the PZT where it is not covered by the restraining layer. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. The restraining layer can be one or more active layers of PZT material that act in the opposite direction as the main PZT layer. The restraining layer(s) may be thinner than the main PZT layer.

A piezoelectric thin film 3 contains a metal oxide, the metal oxide contains bismuth, potassium, titanium, iron and element M, the element M is at least one of magnesium and nickel, at least a part of the metal oxide is a crystal having a perovskite structure, and a (001) plane, a (110) plane or a (111) plane of the crystal is oriented in a normal direction dn of the surface of the piezoelectric thin film 3.

According to one embodiment, when adjusting a position of a magnetic head by a microactuator, in a case where a difference of an absolute value of a first voltage value obtained by correcting a voltage value applied to the microactuator based on hysteresis and an absolute value of a second voltage value obtained by not correcting the voltage value applied to the microactuator based on the hysteresis is positive, a control unit applies a third voltage value obtained based on the second voltage value to the microactuator, and adjusts shortage of the adjustment executed by the microactuator by controlling at least one of a voice coil motor and/or a microactuator other than a microactuator applying a third voltage value.

According to one embodiment, a magnetic disk device including a disk, a head that writes data to the disk and reads data from the disk, an actuator that is rotationally driven and controls movement of the head mounted above the disk, a microactuator that is mounted on the actuator and finely swings the head in a radial direction of the disk by a piezoelectric element that extends and contracts when a drive voltage based on a bias voltage is applied to the piezoelectric element, and a controller that switches the bias voltage according to an operation state during an access process.

A flexure is described, which includes conductive traces extending from a proximal end of the flexure to a distal end of the flexure. The flexure also includes a plurality of outer gimbal struts configured to define an opening at the proximal end of the flexure. The flexure also includes an oblong feature extending into the opening, the oblong feature defines an aperture. The conductive traces include a first semi-circular conductive trace portion overlapping a first section of the oblong feature at a proximal end of the aperture extending to a distal end of the aperture. The conductive traces include a second semi-circular conductive trace portion overlapping a second section of the oblong feature at a proximal end of the aperture extending to the distal end of the aperture. The first and second semi-circular conductive trace portions define the aperture.

A head driving device includes a head supporting portion supporting a head member, a first beam, a second beam, a first piezoelectric unit including a pair of piezoelectric elements, and a second piezoelectric unit including a pair of piezoelectric elements. When voltage is applied to the piezoelectric elements of the first piezoelectric unit, the piezoelectric elements deform, and a distal end of the first beam moves. The piezoelectric elements of the second piezoelectric unit also deform by application of voltage, and moves a distal end of the second beam in a same direction as the distal end of the first beam.

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

Various illustrative aspects are directed to a data storage device comprising one or more disks; an actuator arm assembly comprising one or more actuator arms, and configured to position the one or more actuator arms over disk surfaces of the one or more disks; one or more fine actuators, disposed on the one or more actuator arms; and one or more processing devices. The one or more processing devices are configured to: output a driver current to the one or more fine actuators, wherein the one or more processing devices are configured to rate limit a rise of the driver current over time during an activation of the driver current to within a selected rate limit of current rise over time.

An apparatus comprises a heat-assisted magnetic recording drive which includes an enclosure having a base and a cover. The drive includes a magnetic recording disk and a head gimbal assembly proximate one of the base and the cover. The HGA supports a slider assembly comprising a laser diode unit. The LDU projects away from the HGA towards one of the base and the cover. An arcuate channel is provided in one of the base and the cover and dimensioned to receive a distal portion of the LDU. The channel has a length that accommodates the distal portion of the LDU along a stroke of the HGA.

An apparatus includes an actuator assembly, a dampening assembly coupled to the actuator assembly, and a vibration sensor assembly coupled to the dampening assembly and coupled to the actuator assembly by way of the dampening assembly. A method includes attaching a dampening assembly to an actuator assembly and attaching a vibration sensor assembly to the dampening assembly. The dampening assembly is positioned between the vibration sensor assembly and the actuator assembly.