US Patent 9039921 Freestanding films with electric field-enhanced piezoelectric coefficients

A method to produce low-temperature sinterable powders which are then subsequently used to fabricate freestanding piezoelectric films with very large electric-field-enhanced piezoelectric response is provided. The −d31 coefficient for PMN-PT layers can be as high as 2000 pm/V, larger than that of commercial single crystalline PMN-PT bulk materials, at 10 kV/cm (or 20 V over the 20-micron film thickness). In contrast to single crystals, the polycrystalline freestanding films are easy to fabricate and can be made into any size. The films are also easily miniaturized. The method can be applied to nearly any piezoelectric material.