Effect of acceptor and donor dopants on ferroelectric and piezoelectric properties of lead zirconate titanate ceramics

Dielectric, ferroelectric and piezoelectric properties of Pb 1− x La x (Zr y Ti 1− y ) 1−( x /4)−(3/4) z Fe z O 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, Weinheim)