FERROELECTRIC PROPERTIES OF (BI1/2PB1/2)(NI1/4TI3/4)O3 FOR NEW PIEZOELECTRIC CERAMICS

Bismuth lead nickel titanate, (Bi1/2Pb1/2)(Ni1/4Ti3/4)O3 (BPNT), is studied on the basis of its ferroelectric, piezoelectric and mechanical properties as a new group of piezoelectric ceramics. The crystal phase of BPNT is a tetragonal perovskite type with a large crystalline anisotropy. The Curie temperature, T(c), is 430-degrees-C and the dielectric constant, epsilon(s), is 690 at room temperature. The D-E hysteresis loop is observed with a large remanent polarization, P(r) = 31.4 muC/cm2, and a large coercive field, E(c) = 45.4 kV/cm. The electromechanical coupling factors, k(t) and k(p), in the thickness and the planar modes are 49% and 31%, respectively. The mechanical strength was slightly higher than that of the conventional PZT system.