An electroactive ceramic may be incorporated into a transparent optical element and may characterized by an average grain size of less than 200 nm, a relative density of at least 99%, and a transmissivity within the visible spectrum of at least 50%, while maintaining a d.sub.33 value of at least 20 pC/N. Optical properties of the electroactive ceramic, including transmissivity, haze, and clarity may be substantially unchanged during actuation of the optical element and the attendant application of a voltage to a layer of the electroactive ceramic.

An electroactive ceramic may be incorporated into a transparent optical element and may characterized by an average grain size of less than 200 nm, a relative density of at least 99%, and a transmissivity within the visible spectrum of at least 50%, while maintaining a d.sub.33 value of at least 20 pC/N. Optical properties of the electroactive ceramic, including transmissivity, haze, and clarity may be substantially unchanged during actuation of the optical element and the attendant application of a voltage to a layer of the electroactive ceramic.

An electroactive ceramic may be incorporated into a transparent optical element between transparent electrodes and may characterized by a preferred crystallographic orientation. The preferred crystallographic orientation may be aligned along a polar axis of the electroactive ceramic and substantially parallel to each of the electrodes. Optical properties of the optical element, including transmissivity, haze, and clarity may be substantially unchanged during actuation thereof and the attendant application of a voltage to the electroactive ceramic.

A piezoelectric composite material includes a cross-linker and a plurality of ceramic fibers disposed in the cross-linker. The ceramic fibers include ABO.sub.3 oxide. A-site represents Pb.sub.xLa.sub.y containing lead (Pb) and lanthanum (La). In Pb.sub.xLa.sub.y, x ranges from 0.920 to 0.950, and y ranges from 0.050 to 0.080.

There is disclosed a piezoelectric ceramic having the composition: a[PbTiO.sub.3]-b[SrTiO.sub.3]-c[BiFeO.sub.3]-d[(K.sub.xBi.sub.1-x)TiO.sub.3]; wherein 0.4<x<0.6; 0.1<a<0.4; 0.01<b0.2; c0.05; d0.01; and a+b+c+d=1 optionally comprising an A- or B-site metal dopant in an amount of up to 2 at. %.

Disclosed is a focused ultrasonic piezoelectric actuator having a novel type of piezoelectric device for focusing ultrasonic waves. The focused ultrasonic piezoelectric actuator includes a dome-shaped piezoelectric body for focusing ultrasonic waves and a rim configured to facilitate focusing of ultrasonic waves of the body and injection of the dome-shaped piezoelectric body during a powder injection molding process, remove warpage of the dome-shaped body during a sintering process, and reinforce focusing intensity of the ultrasonic waves. The rim is integrally formed with the body. Accordingly, in the focused ultrasonic piezoelectric actuator, a dome-shaped focused ultrasonic piezoelectric actuator for focusing ultrasonic waves using a thickness vibration mode at a MHz frequency band is easily manufactured by a powder injection molding method, and thus an ultrasonic focusing effect is maximized.

Disclosed is a focused ultrasonic piezoelectric actuator having a novel type of piezoelectric device for focusing ultrasonic waves. The focused ultrasonic piezoelectric actuator includes a dome-shaped piezoelectric body for focusing ultrasonic waves and a rim configured to facilitate focusing of ultrasonic waves of the body and injection of the dome-shaped piezoelectric body during a powder injection molding process, remove warpage of the dome-shaped body during a sintering process, and reinforce focusing intensity of the ultrasonic waves. The rim is integrally formed with the body. Accordingly, in the focused ultrasonic piezoelectric actuator, a dome-shaped focused ultrasonic piezoelectric actuator for focusing ultrasonic waves using a thickness vibration mode at a MHz frequency band is easily manufactured by a powder injection molding method, and thus an ultrasonic focusing effect is maximized.

A multilayer electronic component includes a dielectric layer and internal electrodes; wherein the dielectric layer includes a rare earth element, Mn, and Ti. The rare earth element includes a first rare earth element including Dy and Tb, and a second rare earth element including a rare earth element different from the first rare earth element. The number of moles of the rare earth element is defined as RE, the number of moles of Dy is defined as A1, the number of moles of Tb is defined as A2 based on 100 moles of Ti included in the dielectric layer, and 0.5 mol?RE?0.9 mol and 1<A2/A1 are satisfied. The number of moles of the second subcomponent element based on 100 moles of Ti included in the dielectric layer is 0.2 mole or more and 0.5 mole or less.

A ceramic material for capacitors using multilayer technology of formula (I): Pb.sub.(11.5a)A.sub.aB.sub.b(Zr.sub.1xTi.sub.x).sub.(1cdef)C.sub.eSi.sub.cO.sub.3+y.Math.PBO wherein A is selected from the group consisting of La, Nd, Y, Eu, Gd, Tb, Dy, Ho, Er and Yb; C is selected from the group consisting of Ni and Cu; and 0<a<0.12, 0.05x0.3, 0c<0.12, 0.001<e<0.12 and 0y<1.

A nano-composite structure comprises of an amorphous matrix with embedded nano-crystallites. The nano-crystallites are precipitated from the amorphous matrix via heat treatment of a solution mixture of metal salts or metalorganic compounds to an appropriate temperature range and with a suitable duration, or heating of a mixture of non-crystalline compounds. The nano-crystallites are self-assembled in the amorphous matrix without forming agglomerates or distinguished grain boundaries. The nano-composite structure can be used for transparent display, transparent optical ceramics, protection armor, nuclear protection, pulsed power, high voltage electronics, high energy storage system and high power microwave systems.