Abstract: The invention relates to a miniaturizable motor (1) comprising a rotor (12) that is driven by a hollow cylindrical piezo oscillator (2). Said rotor is effectively connected to a frictional face (13) of the piezo oscillator while a main electrode or counter electrode (3) and excitation electrodes (4, 5, 6) are disposed on the surface of the hollow cylinder. The hollow cylindrical piezo oscillator is made of a monocrystalline material with a trigonal crystal system which is provided with three main electrical axes that are placed at a 120° angle relative to each other as well as an optical axis. Said optical axis encloses a 90° angle along with the point of intersection of the electrical axes while coinciding with the longitudinal axis of the hollow cylindrical piezo oscillator. Furthermore, the axial axis of symmetry of the respective excitation electrode intersects one of the main electrical axes while said axial axis of symmetry extends parallel to the optical axis.

Abstract: A piezoelectric stack (1) has alternately successive piezoelectric layers (2) and inner electrode layers (3, 4) which are alternately electrically connected to two outer electrodes (7, 8) which are arranged on the outer side (5, 6) of the piezoelectric stack (1). The piezoelectric stack (1) also has at least one safety layer (9, 40, 50) which is arranged between two successive piezoelectric layers (2) instead of one of the inner electrode layers (3, 4). The safety layer (9, 40, 50) is structured in such a manner that it has an internal interruption (13, 44, 45, 53) which is configured in such a manner that the safety layer (9, 40, 50) does not form an electrical contact between the two outer electrodes (7, 8) if it contact-connects both outer electrodes (7, 8) and is electrically conductive.

Abstract: A piezoelectric multilayer component includes a stack of piezoceramic layers and electrode layers arranged one above another. At least one piezoceramic layer is printed with a layer structured according to a predefined pattern in a piezoelectrically inactive zone of the stack. The structured layer has at least one connecting element by which piezoceramic layers that are adjacent in the stacking direction are mechanically connected to one another with a first strength. The structured layer has interspaces filled at least in part with piezoceramic material of the adjacent piezoceramic layers. The adjacent piezoceramic layers in the interspaces are mechanically connected to one another with a second strength, which is less than the first strength.

Abstract: An example flexoelectric piezoelectric composite has a piezoelectric response, which may be a direct piezoelectric effect, a converse piezoelectric effect, both effects, or only one effect. The flexoelectric composite comprises a first material, which may be substantially isotropic, the first material being present in a shaped form. The shaped form gives a piezoelectric response due to a flexoelectric effect in the first material. The shaped form may have ?m symmetry, or a polar variant of this form such as 4 mm symmetry.

Abstract: A multi-layer piezoelectric element of high durability wherein the internal electrodes and the external electrodes do not break even when operated continuously over a long period of time under high electric field and high pressure is provided. The first multi-layer piezoelectric element according to the present invention comprises a stack formed by stacking piezoelectric layers and internal electrodes alternately one on another and external electrodes formed on a first side face and on a second side face of the stack, wherein one of the adjacent internal electrodes is connected to the external electrode formed on the first side face and the other internal electrode is connected to the external electrode formed on the second side face, and the external electrodes include an electrically conductive material and glass and is formed from a porous electrically conductive material that has a three-dimensional mesh structure.

Abstract: A ceramic material includes lead zirconate titanate, which additionally contains Nd and Ni.

Abstract: The present invention relates to piezoelectric vibrators such as a resonator used as a timing element, discriminator, filter or the like, and fabricating methods thereof. The piezoelectric vibrators of the present invention may be fabricated by forming a piezoelectric body of piezoelectric sheets, of which the thickness is controlled, and simultaneously sintering the sheets along with cover layers, on which grooves are formed. Also, the piezoelectric vibrator of the present invention is fabricated by laminating the piezoelectric sheets, of which the thickness is controlled, providing internal electrodes between the sheets, and forming external electrodes insulated from the internal electrodes.

Abstract: The present invention provides a MEMS piezoelectric switch that has an articulated unimorph bridge attached to a substrate. The bridge includes a passive layer of zirconia and at least one silicon-based material, an active layer of a piezoelectric material that has a high piezoelectric coefficient, at least one pair of interdigitated electrodes, disposed on the top surface of the active layer and across which the bias voltage is applied, and a top contact electrode. A bottom contact electrode is provided on the substrate, and signals flow through the switch when the top and bottom contact electrodes contact one another.

Abstract: The multi-layer piezoelectric element comprises a stack having an active portion constituted from at least one piezoelectric layer and a plurality of internal electrodes consisting of first and second internal electrodes placed one on another, the active portion being subjected to expansion and contraction in response to a voltage applied across the first internal electrode and the second internal electrode, and external electrodes formed on two side faces of the stack with one thereof being connected to the first internal electrode and the other connected to the second internal electrode, wherein each of the external electrodes is constituted from three or more layers including a first layer formed in contact with the side face of the stack and a second layer formed on the first layer, to provide a multi-layer piezoelectric element having high durability.

Abstract: A piezoelectric film of the present invention has a surface roughness value P-V of not more than 170.0 nm, which is defined by a difference between a maximum height (peak value P) and a minimum height (valley value V) on a film surface, a piezoelectric constant d31 greater than 150 pC/N and a breakdown voltage of 80 V or more, which is defined by an applied voltage that results in a current value of 1 ?A or more.

Abstract: A piezoelectric element includes: a base substrate; a lower electrode formed above the base substrate; a ferroelectric layer formed above the lower electrode; and an upper electrode formed above the ferroelectric layer, wherein an angle of a corner defined by a side surface of the ferroelectric layer and a top surface of the base substrate is between 45° and 75°.

Abstract: When a film containing constituent elements of a target is formed on a substrate through a vapor deposition process using plasma with placing the substrate and the target to face to each other, the film is formed with surrounding the substrate with a wall surface having the constituent elements of the target adhering thereto, and applying a physical treatment to the wall surface to cause the components adhering to the wall surface to be released into the film formation atmosphere.

Abstract: A piezoelectric device of the present invention includes a piezoelectric material and lower and upper electrodes for applying an electric field to the piezoelectric material. The upper electrode is patterned, and an edge portion of the upper electrode is provided with a structure where an intensity of the electric field exerted on the piezoelectric material gradually decreases along a direction from a central portion toward an edge surface of the upper electrode when the electric field is applied to the piezoelectric material.

Abstract: A main component has a general formula of {(1?x)(K1-a-bNaaLib)m(Nb1-c-dTacSbd)O3?x(M10.5Bi0.5)nM2O3} (wherein M1 is Ca, Sr or Ba, M2 is Ti, Zr or Sn, 0.005?x?0.5, 0?a?0.9, 0?b?0.3, 0?a+b?0.9, 0?c?0.5, 0?d?0.1, 0.9?m?1.1, and 0.9?n?1.1). At least one specific element selected from the group consisting of In, Sc, Y, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Lu is contained at as in sample numbers 46 to 48, 0.1 to 10 mol in total per 100 mols of the main component (preferably, 1.5 to 10 mol). This provides a piezoelectric ceramic composition and a piezoelectric ceramic electronic component that can have a desired high piezoelectric d constant in a consistent and highly efficient manner in both a very low electric field and a high electric field.

Abstract: There are provided methods for creating energy conversion devices based on the giant flexoelectric effect in non-calamitic liquid crystals. By preparing a substance comprising at least one type of non-calamitic liquid crystal molecules and stabilizing the substance to form a mechanically flexible material, flexible conductive electrodes may be applied to the material to create an electro-mechanical energy conversion device which relies on the giant flexoelectric effect to produce electrical and/or mechanical energy that is usable in such applications as, for example, power sources, energy dissipation, sensors/transducers, and actuators.

Abstract: Methods, systems, and apparatus for drive a pumping chamber of a fluid ejection system are disclosed. In one implementation, the actuator for drive the pumping chamber includes a continuous piezoelectric layer between a pair of drive electrodes and a continuous reference electrode. The pair of drive electrodes includes an inner electrode and an outer electrode surrounding the inner electrode. The actuator is further coupled to a controller which, during a fluid ejection cycle, applies a negative voltage pulse differential to the outer electrode to expand the pumping chamber for a first time period, then applies another negative voltage pulse differential to the inner electrode during a second time period after the first time period to contract the pumping chamber to eject a fluid drop.

Abstract: A method of manufacturing a ceramic includes forming a film which includes a complex oxide material having an oxygen octahedral structure and a paraelectric material having a catalytic effect for the complex oxide material in a mixed state, and performing a heat treatment to the film, wherein the paraelectric material is one of a layered catalytic substance which includes Si in the constituent elements and a layered catalytic substance which includes Si and Ge in the constituent elements. The heat treatment includes sintering and post-annealing. At least the post-annealing is performed in a pressurized atmosphere including at least one of oxygen and ozone. A ceramic is a complex oxide having an oxygen octahedral structure, and has Si and Ge in the oxygen octahedral structure.

Abstract: An article comprises first and second electrically responsive elements having a cutting plane which is perpendicular to an x-dimension for separating the elements. The conductive elements of the conductive layers are alternatingly exposed to one of the two opposing faces of the conductive element.

Abstract: A piezoelectric actuator includes external conductors formed on an outer surface of a piezoelectric component. The external conductors each include a thick-film conductor and a conductive reinforcer. The thick-film conductor is provided with a first thick-film conductor formed on the outer surface of the piezoelectric component, second thick-film conductors which are formed on part of an outer surface of the first thick-film conductor and which are in surface-contact with the outer surface of the first thick-film conductor. The conductive reinforcer is attached to outer surfaces of the second thick-film conductors.

Abstract: A piezoelectric element includes a lower electrode film disposed on a substrate, a piezoelectric layer 70 disposed on the lower electrode film, a upper electrode film 80 disposed on the piezoelectric layer 70, wherein the piezoelectric layer 70 is formed of a plurality of columnar grains 70a, and the upper electrode film 80 conforms to the surface shape of each of the grains 70a of the piezoelectric layer 70.

Abstract: The present invention provides a method of depositing a metallic layer on to a surface of a piezoelectric substrate, which method comprises the application of cold spraying to deposit the metallic layer or layers.

Abstract: Provided are a polymer and a polymer actuator including the polymer. The polymer is cross-linked by a cross-linking agent. When the polymer is used in the polymer actuator, the polymer actuator shows a high strain and may be stably operated at high temperatures.

Abstract: In an exemplary method a profile outline of a desired piezoelectric vibrating piece is formed on a surface of a piezoelectric wafer. The piece includes a base and at least two arms extending from the base. On a surface of the wafer within the profile outline, a first metal layer is formed comprising at least one of Cr, Ni, and Ti. A second metal layer, of Au and/or Ag, is formed on at least one selected region of the first metal layer. An electrode pattern is formed on at least one selected region of the second metal layer. From at least one selected location within the electrode pattern, the second metal layer is peeled away to form an electrode on the piezoelectric vibrating device comprising the first metal layer but not the second metal layer.

Abstract: Thin-film bulk acoustic resonators include a resonator body (e.g., silicon body), a bottom electrode on the resonator body and a piezoelectric layer on the bottom electrode. At least one top electrode is also provided on the piezoelectric layer. In order to inhibit process-induced variations in material layer thicknesses from significantly affecting a desired resonant frequency of the resonator, the top and bottom electrodes are fabricated to have a combined thickness that is proportional to a target thickness of the piezoelectric layer extending between the top and bottom electrodes.

Abstract: An electrode structure of a piezoelectric element is provided. The piezoelectric element 23a (23b) constitutes a piezoelectric actuator 19 attached to an attaching part 30 of an object, to minutely move a movable part 15 of the object relative to a base part 13 of the object according to deformation occurring on the piezoelectric element in response to a power applied state of the piezoelectric element. The electrode structure includes an electrode 41a formed on one of a pair of electrode forming faces 31a and 31b of the piezoelectric element on an inner side of a peripheral zone 31a1, the peripheral zone being defined along the periphery of the electrode forming face 31a on which the electrode is formed. The electrode structure also includes a non-electrode part 51 formed in the peripheral zone. Even if the peripheral zone 31a1 of the electrode forming face 31a having a short-circuit causing possibility touches the attaching part 30, no short circuit occurs.

Abstract: Provided are a piezoelectric thin film including a lead-free ferroelectric material and exhibiting high piezoelectric performance comparable to that of PZT, and a method of manufacturing the piezoelectric thin film. The piezoelectric thin film of the present invention has a multilayer structure in which a metal electrode film having a plane orientation of (100), a (Bi,Na)TiO3 film, and a (Bi,Na,Ba)TiO3 film having a plane orientation of (001) are laminated in this order. The piezoelectric thin film of the present invention can be applied to a wide range of fields and uses. For example, with the piezoelectric thin film of the present invention, an angular velocity sensor of the present invention having high sensitivity and a piezoelectric generating element of the present invention having excellent power generation characteristics can be constructed.

Abstract: In a piezoelectric device, a first electrode, a first piezoelectric film, a second piezoelectric film, and a second electrode are formed in this order on a first electrode formed above a surface of the substrate, and an intermediate electrode is arranged between the first and second piezoelectric films. Each of the first and second piezoelectric films has a thickness of 10 micrometers or smaller, and has a first surface facing toward the substrate and a second surface opposite to the first surface. At least one of the first and second surfaces has an arithmetic average surface roughness (Ra) of 0.5 micrometers or smaller.

Abstract: An acoustic wave device having an improved frequency-temperature characteristic and in which a spurious response of the higher order mode is suppressed includes a piezoelectric substrate made of LiNbO3, a SiO2 layer laminated on the piezoelectric substrate, and an IDT electrode disposed in an interface of the piezoelectric substrate and the SiO2 layer, wherein ? and ? of Euler angles expressed by (?, ?, ?) of LiNbO3 substrate satisfy ?=0° and 80°???130°, respectively. The acoustic wave device using an acoustic wave primarily having an SH wave, wherein ? is set to satisfy 5°???30°.

Abstract: The invention relates to a piezochrome composite comprising a matrix of a piezoelectric material with particles of a spin transition compound. The invention also relates to a device that beside said composite also comprises a voltage supply connected to electrodes provided on said matrix. In one embodiment is this device provided with a temperature stabilising device.

Abstract: There is disclosed a piezoelectric/electrostrictive element which can be used as a sensor, even if a piezoelectric/electrostrictive layer cracks. Provided is a piezoelectric/electrostrictive element 10 comprising a substrate 11, a lower electrode layer 12 secured onto the substrate 11, and a piezoelectric/electrostrictive layer 13 secured onto the lower electrode layer 12, and the coverage of the lower electrode layer 12 with respect to the substrate 11 is 98% or less.

Abstract: An under bump metal film formed on a substrate includes a diffusion-resistant barrier layer made of a platinum group metal film, and an aluminum-based stress relaxation layer formed under the diffusion-resistant barrier layer.

Abstract: A generator-motor apparatus includes a control circuit, an alternator, electrode plates, and switching devices. The electrodes plates have a substantial horseshoe shape, and are provided on an end surface of the alternator so as to surround a rotating shaft of the alternator. Each of the switching devices is formed by sandwiching a MOS transistor between two electrodes, and has a can structure for sealing the internal space of the switching device using a resin. The switching devices are directly attached to the electrode plate by means of soldering, and the switching devices are directly attached to the electrode plate by means of soldering. The control circuit controls the switching devices. The switching devices drive the alternator as an electric motor or an electric power generator.

Abstract: A probe for an ultrasonic diagnostic apparatus and a method of manufacturing the same are disclosed. The probe includes a backing layer having a first electrode part, a piezoelectric member connected to the first electrode part, a sound matching layer having a second electrode part connected to the piezoelectric member, and a PCB connected to the first and second electrode parts. The probe is configured to allow easy and rapid connection between the piezoelectric member and the PCB while providing improved durability and uniformity to a connected part between the piezoelectric member and the PCB, thereby enabling easy and rapid manufacture of the probe while preventing deterioration in performance caused by defective connection between the piezoelectric member and the PCB.

Abstract: The invention relates to an actuator for converting between mechanical and electrical energy comprising -at least two electrodes; and -an electroactive polymer, comprising aromatic moieties in the chain and flexible moieties in the chain, the polymer further comprising side groups bound to the chain, which side groups are selected from the group consisting of polar side groups and side groups comprising an aromatic moiety. The invention further relates to a novel electroactive polymer comprising polar side groups bound to the chain.

Abstract: A printed circuit board includes a multiple-layer electrical circuit board and a nickel arm, wherein the nickel arm has an unconnected end located opposite to the connected end of the nickel arm, wherein the nickel arm has a front side and a backside located opposite to the front side of the nickel arm, wherein the backside of the nickel arm is located adjacent to the multiple layer electrical circuit board. A dimple is formed at the unconnected end of the nickel arm and on the front side of the nickel arm. An air gap is formed between the backside of the arm and the multiple layer electrical circuit board, wherein the air gap permits the arm to flex within the air gap. A lead zirconium titanate element is laminated to the printed circuit board, wherein the dimple on the front side of the arm contacts a surface of the lead zirconium titanate element, wherein a restoring spring force of the nickel arm maintains electrical contactivity between the dimple and the lead zirconium titanate element.

Abstract: A honeycomb-type piezoelectric/electrostrictive element includes a honeycomb structure section having a partition wall which partitions cells passing through the honeycomb structure section in an axial direction, and an electrode as an internal electrode disposed on an inner wall surface of the cell to internally cover the entire inner wall surface, wherein the partition wall is formed of a piezoelectric/electrostrictive body, and the honeycomb structure section can be deformed by applying a voltage between the electrodes disposed in the cells adjacent through the partition wall.

Abstract: A bistable electroactive polymer transducer is provided for electrically actuated deformation of rigid electroactive polymer members. The polymers have glass transition temperatures (Tg) above ambient conditions and turn into rubbery elastomers above Tg and have high dielectric breakdown strength in the rubbery state. They can be electrically deformed to various rigid shapes with maximum strain greater than 100% and as high as 400%. The actuation is made bistable by cooling below Tg to preserve the deformation. The dielectric actuation mechanism includes a pair of compliant electrodes in contact with a dielectric elastomer which deforms when a voltage bias is applied between the pair of electrodes. In some of the transducers of the present invention, the dielectric elastomer is also a shape memory polymer. The deformations of such bistable electroactive polymers can be repeated rapidly for numerous cycles.

Abstract: Piezoelectric frames are disclosed that include a tuning-fork type piezoelectric vibrating piece. The vibrating piece has at least a pair of vibrating arms that extend in a longitudinal direction (e.g., Y-direction) from a first end edge of a piezoelectric base, and at least one excitation electrode on the pair of vibrating arms. Respective supporting arms extend in the longitudinal direction, outboard of each vibrating arm. The vibrating piece is surrounded by and attached to a frame portion also made of piezoelectric material. A pair of connecting portions connects the supporting arms to the frame portion. The connecting portions extend from respective supporting arms to the frame portion in a direction that intersects the longitudinal direction. The connecting portions are connected to the frame portion at designated locations that are more than 50% of the designated length of the vibrating piece from the second end edge of the base.

Abstract: There is provided an actuator element which can be driven at low voltages, is operated stably in air and in vacuo with a quick response, exhibits a large degree of displacement and a large displacement force, has high mechanical strength including flexibility, thus giving long-term durability for repeated use, can be produced by a very simple method, can be formed into a small size because of a simple structure, and can be put into practical use in wide applications.

Abstract: There is provided a piezoelectric resonant element having excellent electrical characteristics in which spurious is suppressed. The piezoelectric resonant element (10) is constituted by sticking a pair of oscillatory electrodes (12, 13), respectively, to both major surfaces of a rectangular piezoelectric substrate (11). In the nonopposing regions of both the oscillatory electrodes (12, 13), extending portions (12c, 13c) are provided to extend in the opposite directions outward from the center X of the opposing region.

Abstract: A piezoelectric device including: a piezoelectric element having, on a surface of a piezoelectric body, an exciting electrode and a drawing electrode that is electrically coupled to the exciting electrode and draws an electrode to an external section, and a substrate bonded to the drawing electrode with a metallic brazing material, in that: the piezoelectric element contains a connecting electrode connecting the exciting electrode with the drawing electrode; and the connecting electrode and/or the exciting electrode contains an underlying layer provided on the surface of the piezoelectric body and a surface layer section provided on a surface of this underlying layer, wherein: the underlying layer is provided using the metallic brazing material and a metallic material of adverse wettability; and a portion of the surface layer section is removed in a manner that the exciting electrode and the drawing electrode are separated.

Abstract: An ultrasonic probe is provided which includes a piezoelectric vibrator having an earth electrode and a signal electrode on a rear surface, an acoustic matching layer disposed on a front surface side of the piezoelectric vibrator, a packing material disposed on the rear surface of the piezoelectric vibrator, and a flexible printed circuit that is interposed between the piezoelectric vibrator and the packing material to cover the entire rear surface of the piezoelectric vibrator and has an earth wiring layer and a signal wiring layer. The earth wiring layer and the signal wiring layer are exposed from a surface facing the piezoelectric vibrator of the flexible printed circuit so as to be electrically connected to the earth electrode and the signal electrode through an exposed surface of the earth wiring layer and an exposed surface of the signal wiring layer, respectively.

Abstract: A solid electrolyte polymer including a cross-linked polyvinylidene fluoride (PVDF)-based polymer, and a polymer actuator including the cross-linked PVDF-based polymer and an electrolytic material.

Abstract: A piezoelectric thin film resonant element includes a resonant portion having a laminate structure made up of a lower electrode, an upper electrode and a piezoelectric film arranged between these two electrodes. The lower electrode has an ellipsoidal plan-view shape and an outer circumference formed with an inclined portion inclined at an angle (about 30° for example) lying within a range of 25° through 55°. The upper electrode has an ellipsoidal plan-view shape. An additional film is provided on the upper electrode at a portion corresponding to the inclined portion of the lower electrode.

Abstract: A liquid ejecting head includes: pressure generation chambers which communicate with nozzle orifices; and piezoelectric elements which induce pressure change in the pressure generation chambers and each include a first electrode, a piezoelectric body layer formed on the first electrode, and a second electrode formed on the side opposite to the first electrode of the piezoelectric body layer, wherein the piezoelectric body layer includes two dielectric films having the substantially same interstitial distance and an intervening layer provided between the two dielectric films and having a different interstitial distance from that of the dielectric film.

Abstract: Wafer-level processing of making outer peripheral ends (beveled portions) of piezoelectric oscillating pieces thinner than center portion sides is made possible easily and at low cost. A metal film which is a mask of a piezoelectric substrate and a photoresist film which is a mask of the metal film and has a pattern with which connection support portions supporting piezoelectric oscillating pieces on the piezoelectric substrate are formed are stacked on the piezoelectric substrate in this order from the substrate side, and by etching with the photoresist film and the metal film used as masks, contours of the plural piezoelectric oscillating pieces are formed in the piezoelectric substrate.

Abstract: A piezoelectric thin film element includes a bottom electrode, a piezoelectric layer and a top electrode on a substrate. The piezoelectric layer includes as a main phase a perovskite-type oxide represented by (NaxKyLiz)NbO3 (0<x<1, 0<y<1, 0<z<0.2, x+y+z=1), and the bottom electrode includes a surface roughness of not more than 0.86 nm in arithmetic mean roughness Ra or not more than 1.1 nm in root mean square roughness Rms.

Abstract: A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

Abstract: A piezoelectric actuator includes a metallic vibration plate, an insulating layer, a plurality of individual electrodes, a piezoelectric layer and a common electrode. The insulating layer is formed on the top surface of the vibration plate. The individual electrodes are formed on the top surface of the insulating layer. The piezoelectric layer is formed on the top surfaces of the individual electrodes. The common electrode is formed on the top surface of the piezoelectric layer over the individual electrodes. A plurality of terminals and a plurality of wirings are formed on the top surface of the insulating layer. Each of the terminals is associated with one of the individual electrodes. Each of the wirings connects one of the individual electrodes and the associated terminal.

Abstract: Providing a manufacturing method of a piezoelectric element by which even if an electrode and a piezoelectric film stacked on a substrate are baked at a high temperature, the electrode does not oxidize and mutual diffusion between the substrate, the electrode and the piezoelectric film may be suppressed. The electrode is adapted as a laminated layer body which includes an electroconductive oxide layer, a mixture layer having an electroconductive oxide and electroconductive metal, and an electroconductive metal layer including the electroconductive metal from a substrate side, and the mixture layer above is adapted as a graded composition structure in which a ration of the electroconductive oxide is highest in an interface with the electroconductive oxide layer and lowest in an interface with the electroconductive metal layer.