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.

The piezoelectric composition is represented by the following Chemical Formula (1):
x[Bi.sub.mFeO.sub.3]-y[Ba.sub.mTiO.sub.3]-z[Sr.sub.mTiO.sub.3](1)
wherein 0.5x0.8, 0.02y0.4, 0.02z0.2, x+y+z=1, and 0.96m1.04.

A piezoelectric composition comprises a plurality of crystal particles, wherein the piezoelectric composition includes bismuth, iron, barium, titanium, and oxygen; the crystal particles include a core and a shell covering the core; the average value of the contents of bismuth in the cores is expressed as C.sub.CORE % by mass, the average value of the contents of bismuth in the shells is expressed as C.sub.SHELL % by mass, and the C.sub.CORE is lower than the C.sub.SHELL; and the number of all the particles comprised in the piezoelectric composition is expressed as N, the number of the crystal particles including the core and the shell is expressed as n, and n/N is 0.10 to 1.00.

A piezoelectric PTZT film is formed of a metal oxide having a perovskite structure including Pb, Ta, Zr, and Ti, in which the metal oxide further includes carbon, and a content of the carbon is 80 to 800 ppm by mass. In a process for producing a liquid composition for forming a piezoelectric film, a Ta alkoxide, a Zr alkoxide, -diketones, and a diol are refluxed, a Ti alkoxide is added into a first synthesis solution obtained by the refluxing, and then refluxing is performed again, a Pb compound is added into a second synthesis solution obtained by performing the additional refluxing, and then refluxing is performed again, a solvent is removed from a third synthesis solution obtained by performing the additional refluxing, and then, dilution with alcohol is performed, to produce the liquid composition for forming a piezoelectric PTZT film.

A piezoelectric ceramic, which does not contain lead as a constituent element, is characterized in that: its primary component is a perovskite compound expressed by the composition formula (Bi.sub.0.5x/2Na.sub.0.5x/2Ba.sub.x)(Ti.sub.1yMn.sub.y)O.sub.3 (where 0.01x0.25, 0.001y0.020); and the coefficient of variation (CV) in grain size among the grains contained therein is 35 percent or lower. The piezoelectric ceramic presents an improved dielectric loss tangent tan .

The present disclosure relates to piezoelectric compositions of Formula I comprising Lead ZirconateLead Titanate solid solution. The disclosure further relates to a method of obtaining said composition, method of preparing/fabricating piezoelectric component(s) and piezoelectric component(s)/article(s) obtained thereof. The piezoelectric composition and articles of the present disclosure show excellent electromechanical characteristics along with very large insulation resistance (IR).

A piezoelectric material for a combustion pressure sensor, a method for producing the piezoelectric material, and a combustion pressure sensor using the piezoelectric material are provided. The piezoelectric material of the present invention includes a single crystal containing Ca, Ta, an element M (M is Al or Ga), Si, and O, the single crystal has the same crystal structure as the crystal structure of langasite represented by La.sub.3Ga.sub.5SiO.sub.14, and at least the content of the element M is insufficient for the stoichiometric composition represented by Ca.sub.3TaM.sub.3Si.sub.2O.sub.14. Preferably, in a case where the element M is Ga, each content of the Ca and the Si is excessive for the stoichiometric composition, and in a case where the element M is Al, the content of the Ca is excessive for the stoichiometric composition, and the content of the Ta is insufficient for the stoichiometric composition.

A manufacturing method for an ultrasonic fingerprint sensor is provided. The method may include: preparing a sintered ceramic element under incomplete sintering conditions; forming a processed ceramic element by cutting a first surface of the sintered ceramic element along a first direction in pre-designated intervals up to such a depth that leaves a remainder region at a second surface and cutting the second surface of the sintered ceramic element along a second direction perpendicular to the first direction in pre-designated intervals up to such a depth that leaves a remainder region at the first surface; sintering the processed ceramic element under complete sintering conditions; filling an insulation material into troughs formed in the processed ceramic element by the cutting processes; and polishing the first surface and second surface to remove the remainder regions such that piezoelectric rods are exposed while arranged in an array form.

In an exemplary embodiment, a piezoelectric ceramic composition is an alkali niobate-based piezoelectric ceramic composition whose primary component is a compound expressed by the general formula Li.sub.xNa.sub.yK.sub.1xyNbO.sub.3 (where 0<x<1, 0<y<1, and x+y<1), and which contains 100 ppm or more but less than 1000 ppm of fluorine by mass. The alkali niobate-based piezoelectric ceramic composition demonstrates good properties even when sintered at low temperature.

The present invention provides a piezoelectric material not containing lead and potassium, showing satisfactory insulation and piezoelectricity, and having a high Curie temperature. The invention relates to a piezoelectric material includes a main component containing a perovskite-type metal oxide represented by Formula (1): (Na.sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (wherein, 0.80x0.94 and 0.83y0.94), and an additive component containing at least one element selected from Mn and Ni, wherein the content of the Ni is 0 mol or more and 0.05 mol or less based on 1 mol of the perovskite-type metal oxide, and the content of the Mn is 0 mol or more and 0.005 mol or less based on 1 mol of the perovskite-type metal oxide.