A piezoelectric element includes a first electrode, a second electrode, and a thin piezoelectric layer. The thin piezoelectric layer is provided between the first electrode and the first electrode, and is formed of a perovskite type compound oxide which contains potassium, sodium, and niobium. In the piezoelectric layer, in an X-ray diffraction pattern obtained by ??2? measurement, peaks derived from a (002) plane and a (200) plane are provided in a range in which 2? is from 45? to 47?, a peak position of the peak on a high angle side among the peaks satisfies 46.0??2??46.5?, and a difference of 2? between the peak on the high angle side and the peak on a low angle side is greater than 0.60?.

A manufacturing method of an epitaxial thin film piezoelectric element includes: providing a substrate; forming a bottom electrode layer on the substrate by epitaxial growth process; forming a first piezoelectric layer that has c-axis orientation on the bottom electrode layer by epitaxial growth process; forming a second piezoelectric layer that has c-axis orientation and different phase structure from the first piezoelectric layer on the first piezoelectric layer by epitaxial growth process; and forming a top electrode layer on the second piezoelectric layer. The thin film piezoelectric element has good thermal stability, low temperature coefficient and high piezoelectric constant.

Provided is a piezoelectric element including: a first electrode; a piezoelectric layer which is provided over the first electrode; and a second electrode provided on a side of the piezoelectric layer opposite to the first electrode, in which the second electrode includes a first layer which is provided on the piezoelectric layer side, and a second layer which is provided on a side of the first layer opposite to the piezoelectric layer, and the second layer does not contain platinum and covers an end portion of the first layer.

A gallium nitride structure that includes: a substrate; a gallium nitride layer opposed to the substrate and containing gallium nitride as a main component thereof; and a first electrode between the gallium nitride layer and the substrate. The first electrode includes at least one hafnium layer containing a single metal of hafnium as a main component thereof, and the at least one hafnium layer is in contact with the gallium nitride layer.

There is disclosed a piezoelectric thin film element comprising a first electrode, a second electrode and one or more piezoelectric thin films there between characterised in that the thin film element has at least two of: an electrode arrangement in which electrodes are arranged with the one or more piezoelectric thin films so that an electric field applied to a piezoelectric thin film or a portion of a piezoelectric thin film adjacent to the first electrode is lower than an electric field applied to a piezoelectric thin film or a portion of a piezoelectric thin film further from the first electrode when the piezoelectric thin film element actuated; a piezoelectric thin film adjacent to the first electrode in which a layer of the piezoelectric thin film near to the first electrode has a piezoelectric displacement constant which is lower than that of a layer of the piezoelectric thin film further from the first electrode; and a piezoelectric thin film adjacent to the first electrode in which a layer of the piezoelectric thin film near to the first electrode has an elastic modulus which is lower than that of a layer of the piezoelectric thin film further from the first electrode.

A method is provided for growing a fiber structure, where the method includes: obtaining a substrate, growing an array of pedestal fibers on the substrate, growing fibers on the pedestal fibers, and depositing a coating surrounding each of the fibers. In another aspect, a method of fabricating a fiber structure includes obtaining a substrate and growing a plurality of fibers on the substrate according to 1?D printing. In another aspect, a multilayer functional fiber is provided produced by, for instance, the above-noted methods.

A piezoelectric device and a manufacturing method thereof in which a piezoelectric film formed of a thin film of a lead zirconate titanate-based perovskite oxide is formed on a substrate, and at least a first region out of the first region and a second region of the piezoelectric film is irradiated with electromagnetic waves having a wavelength of 230 nm or less in a reducing atmosphere to provide a difference in piezoelectric characteristics between the first region and the second region so that the first region has a smaller absolute value of a piezoelectric constant d.sub.31 and a smaller dielectric loss tan ? than the second region.

An electromechanical transducer element includes a first electrode; an electromechanical transducer film stacked on one surface of the first electrode; a second electrode stacked on the electromechanical transducer film; and wiring formed on the second electrode. In an at least one cross section, each of a boundary, on a second electrode side, of the electromechanical transducer film and a boundary, on a side opposite to the electromechanical transducer film, of the second electrode is a curved shape protruding away from the first electrode. In the at least one cross section, each of a film thickness of the electromechanical transducer film and a film thickness of the second electrode becomes thinner toward end portions from a maximum height portion.

A piezoelectric element includes a substrate, and a lower electrode, a piezoelectric film, an adhesion layer, and an upper electrode provided on the substrate in this order, in which the piezoelectric film has a perovskite structure that is preferentially oriented to a (100) plane and is a composite oxide represented by the compositional formula Pb[(Zr.sub.xTi.sub.1-x).sub.1-yNb.sub.y]O.sub.3, where x satisfies 0<x<1 and y satisfies 0.10?y<0.13, I.sub.(200)/I.sub.(100), which is a ratio between a diffraction peak intensity I.sub.(100) from the perovskite plane and a diffraction peak intensity I.sub.(200) from a perovskite plane as measured by X-ray diffraction method, satisfies 0.85?I.sub.(200)/I.sub.(100)?1.00, and the adhesion layer contains a metal having an ionization energy of 0.34 eV or less.

A method for producing a porous piezoelectric polymer film with a dense surface, includes depositing a polymer solution onto a substrate to form a polymer film including a solvent; evaporating a portion of the solvent to form the dense surface away from the substrate; forming water droplets in interior of the polymer film; and substantially evaporating the water droplets and remaining solvent to form porous interior. A piezoelectric composition includes a piezoelectric material with a porous interior and a dense surface for interfacing with an electrode. A piezoelectric device includes a first electrode; a porous piezoelectric film with a dense surface and porous interior, wherein the porous piezoelectric film is deposited on the first electrode and the dense surface is away from the first electrode; and a second electrode deposited on the dense surface for, together with the first electrode, providing an electrical interface for the porous piezoelectric film.