Structural and electrical properties of sol-gel prepared Sm modified Pb(Zr_0·60Ti_0·40)O₃ ceramics

摘要

Polycrystalline samples of Pb_1-zSm_z(Zr_0·60Ti_·4)_1-z/4O₃ (abbreviated as PSZT), with z=0·07, 0·08, and 0·10, have been prepared by a metal-alkoxide sol-gel method. Preliminary X-ray diffraction and transmission electron microscopic analysis of the compounds suggests the formation of nearly single phase compounds in the tetragonal crystal system. SEM analysis of pellet samples sintered at 1300°C for 7 h shows a uniform distribution of nearly spherical grains throughout the sample surfaces. Detailed studies of dielectric constant and tangent loss of PSZT as a function of temperature (from 30 to 400°C) at 1 and 10 kHz frequencies reveal the existence of di ffuse phase transitions in the samples. The transition temperature T_c, broadening of the permittivity peak, remanent polarisation P_r, and coercive field E_c of PSZT change significantly with increasing Sm3 + doping concentration.