The Structure and the Electrical Properties of Pb_0.95La_0.05[Zr_xTi_(0.95–x)(Mo_1/3,In_2/3)_0.05]_0.9875O₃ Ferroelectric Ceramics

Abstract

The structural, the dielectric, and the piezoelectric properties of new ferroelectric Pb_0.95La_0.05[Zr_xTi_(0.95–x)(Mo_1/3,In_2/3)_0.05]_0.9875O₃(0.46 ≤ x ≤ 0.55) ceramics have been investigated. All the samples were being sintered at a temperature ranging from 1000 to 1180℃ after being compacted in circular discs. The detailed structural and ferroelectric properties were carried out for sintered specimens. The results of X-ray diffraction showed that all the ceramics specimens have a perovskite phase. The phase structure of Pb_0.95La_0.05[Zr_xTi_(0.95–x)(Mo_1/3,In_2/3)_0.05]_0.9875O₃ ceramics was transformed from the tetragonal to the rhombohedral, with an increase in the ratio of Zr/Ti in system. In the present system the MPB that coexists with the tetragonal and rhombohedral phases is a narrow composition region of x = 0.50 – 0.51. The scanning Electron Microscopy (SEM) showed an increase of the mean grain size when the sintering temperature was increased. The dielectric constant ε and the coupling factor K_p reached the maximum values, while the mechanical quality factor Qm and the loss tangent reached the lowest values when x = 0.50. For the composition where x = 0.50, these properties include ε = 5414 (at the Curie temperature), tangδ = 0.039, K_p = 0.67, Q_m = 20 and a Curie temperature of 335℃.