The complex $A(B′B″)O_3$ perovskites are important class of ferroelectrics and piezoelectric materials. Among these perovskites, the lead-based complex perovskites with chemical formular $Pb(B′B″)O_3$ have been of great academic interest because they display interesting phase transition behaviors and possess many industrial applications. Their physical properties such as piezoelectric, dielectric and pyroelectric constants vary drastically with the chemical composition and geometrical distribution of B-site cations in the perovskite crystal lattice.
In this study, we made solid solutions from ordered antiferroelectric PYN and PZ and ferroelectric PT. The purpose of this work is to find out the crystal structure change, dielectric and piezoelectric properties of $(PYN_{0.4}PZ_{0.6})_{1-x}PT_x$ ceramic system for 0≤x≤0.6. Structural analysis by XRD, dielectric constant curves, P-E hysteresis loops and piezoelectric coefficients$(d_{33})$ measurements have been conducted to investigate the phase transition phenomena of this system.
From the X-ray diffraction pattern, the crystal structure changes from the pseudocubic for x≤0.4 to the tetragonal for x>0.4. The dielectric constant measurement reveals diffuse phase transition (DPT) behavior at all concentration. But, at x=0 and x=0.05, they have frequency dependence of apparent transition temperature at the applied frequencies between 100Hz and 100kHz, so we judge these compositions as ‘relaxor’ and ferroelectrics showing ‘relaxor to normal ferroelectric’ phase transition behavior, respectively. At other concentration, there is no frequency dependence. The dielectric maxima, remnant polarization and coercive force gradually increases with $Ti^{4+}$ substitution and abruptly decrease at x=0.6. But the transition temperature($T_c$) and $d_{33}$ gradually increase with increasing PT concentration.
