A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer.

A head suspension assembly includes a support plate, an interconnection member including a metal plate on the support plate, a first insulating layer on the metal plate, a conductive layer on the first insulating layer and forming a pair of connection pads, and a second insulating layer on the conductive layer, a head mounted in the interconnection member, and a piezoelectric element electrically connected to the connection pads and configured to displace the head when a predetermined voltage is applied across the connection pads. At least one opening is formed in each of the connection pads. The piezoelectric element is electrically connected to each of the connection pads by a conductive adhesive that is between the piezoelectric element and each of the connection pads and filled in the opening.

Embodiments of disk drive head suspensions are described that include a spring metal layer. The spring metal layer includes a base region, support arms extending from the base region, and a slider mounting region. The slider mounting region includes a proximal portion, a distal portion, and a pair of motor openings. The motor openings are configured to receive motors such that the longitudinal axes of the motors are non-parallel with the longitudinal axis of the slider mounting region. The suspensions include traces that include a base portion on the base region of the spring metal layer, a spring metal-unsupported portion extending from the base region to the slider mounting region, and a slider mounting portion extending from the spring metal-unsupported portion onto the slider mounting region. And, the suspensions include an insulating layer between portions of the spring metal layer and the conductor layer.

A piezoelectric thin film-stacked body is provided. A piezoelectric thin film-stacked body has a first electrode layer, a first intermediate layer stacked on the first electrode layer, a second intermediate layer stacked on the first intermediate layer, and a piezoelectric thin film stacked on the second intermediate layer, the first intermediate layer includes K, Na, and Nb, the second intermediate layer is a layer causing stress in a compression direction in the piezoelectric thin film, and the piezoelectric thin film includes (K,Na)NbO.sub.3.

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 suspension assembly is described. The suspension assembly includes a load beam, the load beam includes a first set of spring extensions connecting a rigid region and a mounting region of the load beam. The suspension assembly also includes a base plate coupled to the mounting region of the load beam. The base plate includes two hinge members, each of the hinge members includes a second spring extension connected to the first set of spring extensions and coupling the load beam and the base plate. The base plate also includes a bender on a first side of the load beam connected to one of the two hinge members predisposing the rigid region to move from a first position to a second position.

A piezoelectric actuator assembly is described. The piezoelectric actuator assembly includes a first, second and third active piezoelectric layers. The first layer includes a top surface and a bottom surface. The second layer includes a top surface and a bottom surface over the top surface of the first layer. The third layer includes a top surface and a bottom surface over the top surface of the second layer. The first and second layers can define a first effective electrode length. Similarly, the second and third layers can define a second effective electrode length configured to be longer than the first effective electrode length.

According to one embodiment, a disk device includes two magnetic disks opposing each other at intervals of 1.2 to 1.5 mm, and at least two suspension assemblies movable respectively between the two magnetic disks. Each of the suspension assemblies includes a base plate, a load beam extending from the base plate, a tab extending from a distal end of the load beam, a wiring member on the load beam and the base plate, including a gimbal portion, and a magnetic head on the gimbal portion, abutting on a dimple of the load beam via the gimbal portion. The ratio of a distance from a bendable location of the load beam to a center of the dimple with respect to a distance from the center of the dimple to a tip of the tab is 2.8 to 3.8.

According to one embodiment, a microactuator includes a wiring substrate, and a piezoelectric element connected to first and second connecting pads of the wiring substrate. The piezoelectric element includes a piezoelectric substrate, and a first electrode and a second electrode provided on surfaces of the piezoelectric substrate. The first electrode includes a first electrode portion on an end portion on a first main surface. The second electrode includes a fifth electrode portion having an electrode end which faces the first electrode portion across a gap and provided on the first main surface. The piezoelectric element includes a protective insulating layer covering at lease an end portion of the fifth electrode including the electrode end.

According to one embodiment, a magnetic disk device includes a first actuator which actuates a magnetic head portion including a magnetic head, a second actuator which adjusts a position of the magnetic head on a magnetic disk in a radial direction of the magnetic disk, and a control portion which determines a second measurement signal amplitude when a second transfer function is measured in accordance with a first gain estimated value of the second actuator and an amplitude of a first measurement signal amplitude to the second actuator applied when a first transfer function is measured, which calculates a second gain estimated value of the second actuator based on the first transfer function and the second transfer function, and which updates the first gain estimated value, using the calculated second gain estimated value.