Tdk Corporation

Hideaki Sone

Tomohisa Azuma

Dai Matsuoka

Yo Saito

Izuru Soma

Hidetoshi Suzuki

Masahito Furukawa

Masakazu Hirose

Hideharu Moro

Goushi Tauchi

Hideya Sakamoto

Satoko Ueda

Naoki Kawakubo

A piezoelectric ceramic with environmental friendliness including a composition as the main component composed of a composite oxide free from lead (Pb) as a constituent element, and with excellent piezoelectric characteristics such as the relative dielectric constant, the electromechanical coupling factor, and the piezoelectric constant, and a piezoelectric device using the piezoelectric ceramic, are provided. A piezoelectric ceramic including a composition represented by the following general formula as the main component: (K1-x-y-w-vNaxLiyBawSrv)m(Nb1-z-uTaz-Zru)O3 (wherein, x, y, z, w, v, u and m in the formula satisfy the following conditions respectively: 0.4&#x3c;x&#x2266;0.7; 0.02&#x2266;y&#x2266;0.1; 0&#x3c;z&#x2266;0.3; 0&#x3c;w&#x2266;0.01; 0.04&#x2266;v&#x2266;0.07; 0.04&#x2266;u&#x2266;0.07; and 0.95&#x2266;m&#x3c;1).

Piezoelectric ceramic comprising an oxide and piezoelectric device

Provided is a piezoelectric ceramic composition which can increase Qof a resonator and inhibit the resonator from changing its oscillation frequency Funder a low temperature environment. The piezoelectric ceramic composition has a structure represented by the following general formula (1):(PbLnMe)(TiZrMnNb)O&#x2003;&#x2003;(1)where Ln is a lanthanoid element, Me is an alkaline-earth metal element, &#x3b1;&#x3e;0, &#x3b2;&#x3e;0, &#x3b3;&#x2267;0, 0.965&#x2266;&#x3b1;+&#x3b2;+&#x3b3;&#x2266;1.000, 0.158&#x2266;x&#x2266;0.210, y&#x2267;0, z&#x2267;0, and 1&#x2212;(x+y+z)&#x3e;0.

Piezoelectric ceramic composition, piezoelectric element, and resonator

Provided is a piezoelectric ceramic composition which enables the attainment of sufficiently high Qand good temperature characteristics of oscillation frequency Fwhen applied in an oscillator utilizing third harmonic mode of thickness longitudinal vibration. The piezoelectric ceramic composition contains a composite oxide having a perovskite structure. The composite oxide has a composition expressed by the chemical formula (1), while satisfying 0.91&#x2266;&#x3b1;&#x2266;1.00, 0&#x3c;&#x3b2;&#x2266;0.08, 0.125&#x2266;x&#x2266;0.300, 0.020&#x2266;y&#x2266;0.050, and 0.040&#x2266;z&#x2266;0.070(PbLn)(TiZrMnNb)O&#x2003;&#x2003;(1)where Ln signifies at least one element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

Piezoelectric ceramic composition and oscillator

A varistor is provided with a varistor element, and an external electrode disposed on the varistor element. The varistor element contains ZnO as a principal ingredient and contains a rare-earth element and Ca. The external electrode is formed by baking on an outer surface of the varistor element and contains Pt. When the external electrode is formed by baking on the varistor element, a compound of the rare-earth element and Pt and a compound of Ca and Pt are formed near an interface between the varistor element and the external electrode, and exist there. The existence of these compounds enhances the bonding strength between the varistor element and the external electrode.

Varistor and method of producing varistor

A varistor element comprises a varistor element body, a plurality of inner electrode pairs, a connecting conductor, and a plurality of terminal electrodes. The varistor element body has first and second main faces opposing each other. Each inner electrode pair has first and second inner electrodes. The first and second inner electrodes are arranged so as to oppose each other at least partly within the varistor element body. The connecting conductor is arranged on the first main face so as to electrically connect the first inner electrodes in a predetermined inner electrode pair in the plurality of inner electrode pairs to each other. The terminal electrodes are provided so as to correspond to the second inner electrodes in the plurality of inner electrode pairs, and are arranged on the second main face so as to electrically connect with the second inner electrodes.

Varistor element

A powder magnetic core having reduced core losses and increased mechanical strength is provided at low costs. The core is obtained by compressing a ferromagnetic metal powder and an insulating agent and then annealing the compressed body. The ferromagnetic metal powder is made up of a substantially spherical form of ferromagnetic metal particles containing Fe, Al and Si. The core has a permeability of at least 50 at 100 kHz, a core loss of up to 450 kW/m.sup.3 at 100 kHz in an applied magnetic field of 100 mT, and a core loss of up to 300 kW/m.sup.3 at 25 kHz in an applied magnetic field of 200 mT.

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Tokyo, Japan

Hideaki Sone