An electromechanical transducer element includes a first electrode on a substrate, an electromechanical transducer film on the first electrode, and a second electrode on the electromechanical transducer film. The electromechanical transducer film includes a thin line pattern. The thin line pattern includes a plurality of thin lines that are spaced away from each other.

A piezoelectric actuator includes a piezoelectric element that includes a piezoelectric unit including a ferroelectric, which has an asymmetric bipolar P-E curve, a capacitor connected to the piezoelectric unit in series, and a resistor connected to the capacitor in series and connected to the ferroelectric in parallel; and a drive unit that inputs a drive waveform Vd, which includes a DC offset component of which polarity is opposite to polarization of the ferroelectric, to the piezoelectric element to drive the piezoelectric element. A value of a coercive electric field Ec.sub.1, a value of a coercive electric field Ec.sub.2, the capacitance C.sub.s of the capacitor, the capacitance C.sub.pz of the ferroelectric, combined resistance R.sub.p of the resistance of the resistor and the resistance of the ferroelectric, and a fundamental angular frequency ? of the drive waveform satisfy Expressions I to III, wherein

There is provided a ferroelectric thin-film laminated substrate, including a substrate, and further including a lower electrode layer, a ferroelectric thin-film layer, an upper electrode adhesive layer, and an upper electrode layer being sequentially stacked on the substrate, in which: the lower electrode layer is made of platinum or a platinum alloy; the ferroelectric thin-film layer is made of a sodium potassium niobate (typical chemical formula of (K.sub.1-xNa.sub.x)NbO.sub.3, 0.4?x?0.7); the upper electrode layer is made of gold; the upper electrode adhesive layer is made of a metal that has less oxidizability than titanium and can make a solid solution alloy without generating an intermetallic compound with gold; and a part of the upper electrode adhesive layer and a part of the upper electrode layer are alloyed.

A first lamination step of forming lower electrode films on both surfaces of a diaphragm and directly forming a first Pb-containing perovskite oxide film which has a larger thermal expansion coefficient than that of the diaphragm and has a columnar structure on a front surface of the lower electrode film; and a second lamination step of directly forming a second Pb-containing perovskite oxide film on a front surface of the lower electrode film are sequentially performed. The second Pb-containing perovskite oxide film is formed under a condition that a difference between a molar ratio R.sub.A1 of Pb to a B-site element in the first Pb-containing perovskite oxide film and a molar ratio R.sub.B1 of Pb to a B-site element in the second Pb-containing perovskite oxide film Ether the second lamination step is 0.056 or less.

A piezoelectric sensor includes: a piezoelectric sheet which is stretched in a uniaxial direction; an electrode which detects electric charges generated in the piezoelectric sheet; and an optical compensation layer which includes a slow axis stacked on at least one side of the piezoelectric sheet and intersects the uniaxial direction, and optically compensates for a phase difference produced when the piezoelectric sheet is stretched in the uniaxial direction.

An elastic wave filter device includes a piezoelectric film, a high acoustic velocity support substrate in which an acoustic velocity of a propagating bulk wave is larger than an acoustic velocity of a main mode elastic wave propagating in the piezoelectric film, and IDT electrodes in contact with the piezoelectric film. A serial arm resonator and a parallel arm resonator are defined by the IDT electrodes such that, a direction in which tips of first and second electrode fingers are connected defines a tilt angle with respect to a propagation direction of elastic waves excited by the IDT electrodes. A tilt angle of the serial arm resonator is different from a tilt angle of the parallel arm resonator.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

The disclosure discloses a thermal reawakening operation method and system for enhancing polarization of a hafnium-based ferroelectric film, belonging to the field of micro-nanoelectronic technology, which includes the following. S1. Heating is performed on the hafnium-based ferroelectric thin film. S2. A pulse voltage having multiple cycles is applied to the hafnium-based ferroelectric thin film. S3.The hafnium-based ferroelectric thin film is cooled to an initial temperature. In the disclosure, through the thermal reawakening operation, a certain amount of oxygen vacancies are generated, and the non-polarized phase is transformed into the polarized phase, the polarization value of the hafnium-based ferroelectric film can be significantly improved at a low cost and with a simple operation, thereby the performance of the hafnium-based ferroelectric device is significantly improved.

There is provided a piezoelectric actuator including a vibration plate; first and second piezoelectric layers; individual electrodes; a first common electrode arranged between the vibration plate and the first piezoelectric layer; a second common electrode arranged between the first piezoelectric layer and the second piezoelectric layer; a first surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the first common electrode; and a second surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the second common electrode. The piezoelectric actuator further comprises an inspection electrode which is arranged on the second piezoelectric layer at an end portion of the second piezoelectric layer, which is overlapped with the one of the first and second common electrodes, and which is not in conduction with any of the individual electrodes, and the first and second common electrodes.

Acoustic filters are disclosed. A substrate includes a base and an intermediate layer. A piezoelectric plate is attached to the intermediate layer, portions of the piezoelectric plate forming one or more diaphragms spanning respective cavities in the intermediate layer. A conductor pattern on a front surface of the piezoelectric plate includes interdigital transducers (IDTs) of a plurality of resonators, interleaved fingers of each of the IDTs disposed on a respective diaphragm of the one or more diaphragms. A first frequency setting dielectric layer having a first thickness is disposed over the fingers of the IDTs of a first subset of the plurality of resonators. A second frequency setting dielectric layer having a second thickness greater than the first thickness is disposed over the fingers of the IDTs of a second subset of the plurality of resonators, wherein the first subset and the second subset are not identical.