A hybrid structure for a surface acoustic wave device comprises a working layer of piezoelectric material assembled with a support substrate having a lower coefficient of thermal expansion than that of the working layer, and an intermediate layer located between the working layer and the support substrate. The intermediate layer is a sintered composite layer formed from powders of at least a first material and a second material different from the first.

The piezoelectric composition is represented by the following Chemical Formula (1):
x[Bi.sub.mFeO.sub.3]-y[Ba.sub.mTiO.sub.3]-z[Bi.sub.mAlO.sub.3](1)
wherein 0.5x0.7995, 0.2y0.4, 0.0005z0.1, x+y+z=1, 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 particle include a core and a shell having a contents of bismuth higher than that in the core and covering the core; and the total area of the cross sections of the cores exposed to the cross section of the piezoelectric composition is expressed as S.sub.CORE, the total area of the cross sections of the shells exposed to the cross section of the piezoelectric composition is expressed as S.sub.SHELL, and 100.Math.S.sub.CORE/(S.sub.CORE+S.sub.SHELL) is 50 to 90.

A ceramic dielectric including: a bulk dielectric including barium (Ba) and titanium (Ti); a ceramic nanosheet; and a composite dielectric of the bulk dielectric and the ceramic nanosheet.

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.

A piezoelectric material includes a metal oxide containing at least Ba, Ca, Ti, Zr, and Mn, in which the piezoelectric material has a perovskite structure, in which: x, which represents a ratio of a content (mol) of Ca to A (mol) representing a total content of Ba and Ca, falls within a range of 0.10x0.18; y, which represents a ratio of a content (mol) of Zr to B (mol) representing a total content of Ti, Zr, and Mn, falls within a range of 0.055y0.085; and z, which represents a ratio of a content (mol) of Mn to the B (mol), falls within a range of 0.003z0.012, and in which the piezoelectric material satisfies a relationship of 0(|d.sub.31(20u)d.sub.31(20d)|)/|d.sub.31(20u)|0.08, and has a value of 130 pm/V or more for each of |d.sub.31(20u)| and |d.sub.31(20d)|.

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.

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 multilayer actuator includes a primary electrode, a secondary electrode overlapping at least a portion of the primary electrode, and an electroactive layer disposed between and abutting the primary electrode and the secondary electrode. The multilayer actuator further includes a primary antireflective coating overlapping at least a portion of the primary electrode opposite the electroactive layer, a secondary antireflective coating overlapping at least a portion of the secondary electrode opposite the electroactive layer, and a barrier layer overlapping the secondary antireflective coating opposite the secondary electrode.