Abstract

Dielectric, ferroelectric and piezoelectric properties of Pb 1-xLa x(Zr yTi 1-y) 1-(x/4)-(3/4)zFe zO 3 ceramics for z = 0 to 6 mol% prepared by a mixed oxide method were investigated. Fe substitution in lead lanthanum zirconate titanate (PLZT) compositions resulted in a phase transformation from coexisting phases (ferroelectric rhombohedral (FE RH) and ferroelectric tetragonal (FE TET)) to intensified tetragonal phase. Grain size and apparent density increased with increasing acceptor (Fe) content up to 3 mol% in the PLZT system. The optimum dielectric properties (ε RT, ε Tc and tan δ) were observed in 3 mol% Fe-doped PLZT composition and then decreased thereafter. Acceptor (Fe) substitution in the PLZT system influenced the ferroelectric remanent polarization (P r) and spontaneous (P s) polarization, reaching saturation at 6 mol% Fe, while the coercive field (E c) increased up to 3 mol% Fe-doped PLZT composition. The piezoelectric properties are sensitive to acceptor (Fe) modification in the PLZT system which was proved by the decreasing trend of piezoelectric charge coefficient (d 33) up to 3 mol% Fe and then increasing to 6 mol% Fe while the piezoelectric planar coupling coefficient (k p) showed a continuous decreasing trend throughout the series. Dielectric, ferroelectric and piezoelectric properties were characterized as a function of acceptor (Fe) concentration in the PLZT system for possible sensor and actuator applications. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.