Realization of high-energy density polycrystalline piezoelectric ceramics

This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr0.52Ti0.48)O-3](1-x)[(Zn1/3Nb2/3)O-3](x)+yMnCO(3), where x=0.1 and y varies from 0.5 to 0.9 wt %. A piezoelectric material with high energy density is characterized by a high product of piezoelectric voltage constant (g) and piezoelectric strain constant (d). The condition for obtaining large magnitude of g constant was derived to be as parallel to d parallel to=epsilon(n), where epsilon is the permittivity of the material and n is constant having lower bound of 0.5. It was found that for all practical polycrystalline piezoelectric ceramic materials the magnitude of n lies in the range of 1.1-1.30 and as the magnitude of n decreases towards unity a giant enhancement in the magnitude of g was obtained. A two step sintering process was developed to optimize a polycrystalline ceramic composition with low magnitude of n. For the optimized composition the value of g(33) and d(33) was found to be 55.56 x 10(-3) m(2)/C and 291 x 10(-12) C/N, respectively, yielding the magnitude product d(33)center dot g(33) as similar to 16168 x 10(-15) m(2)/N which is significantly higher than the reported values in literature. The magnitude of n for this composition was calculated to be 1.151. This material is extremely promising for immediate applications in the sensing and energy harvesting. (c) 2006 American Institute of Physics.