Patent ID: 8531083

Claim:
A device comprising: a substrate a piezoelectric layer and a tunable layer overlying and supported by the substrate, and a means for biasing the tunable layer; wherein the tunable layer has an acoustic behavior over an operating temperature range under a condition of relatively low applied bias that is substantially different than its acoustic behavior under a condition of relatively high applied bias, wherein the piezoelectric layer and the tunable layer are each formed as a thin film over said substrate, wherein the tunable layer has a highly field-polarizable and lattice-deformable, substantially centrosymmetric structure over an operating temperature range under a condition of relatively low applied bias, and a substantially non-centrosymmetric structure over said operating temperature range under a condition of relatively high applied bias, wherein the dielectric permittivity constant of the tunable layer is at least 100 at low applied bias, wherein the tunable layer is close to its ferroelectric instability but remains paraelectric throughout the operating temperature range of the device when the device is under the condition of relatively low applied bias, and wherein the phase transition temperature from paraelectric to ferroelectric state is just below the operating temperature range of the device, the phase transition temperature range being between approximately 150 kelvins and 200 kelvins.