Phase Diagram and Properties of High <i>T</i> _C / <i>T</i> _R−T <scp> <scp>Pb</scp> </scp> ( <scp> <scp>In</scp> </scp> _1/2 <scp> <scp>Nb</scp> </scp> _1/2 ) <scp> <scp>O</scp> </scp> ₃ – <scp> <scp>Pb</scp> </scp> ( <scp> <scp>Zn</scp> </scp> _1/3 <scp> <scp>Nb</scp> </scp> _2/3 ) <scp> <scp>O</scp> </scp> ₃ – <scp> <scp>PbTiO</scp> </scp> ₃ Ferroelectric Ceramics

Abstract

A ternary ferroelectric ceramic system, (1− x − y ) Pb ( In 1/2 Nb 1/2 ) O 3 – x Pb ( Zn 1/3 Nb 2/3 ) O 3 – y PbTiO 3 ( PIN – PZN – PT , x = 0.21, 0.27, 0.36, 0.42), was prepared using a two‐step precursor method. The phase structure, dielectric, piezoelectric, and ferroelectric properties of the ternary ceramics were systematically investigated. A morphotropic phase boundary ( MPB ) was identified by X ‐ray diffraction. The optimum piezoelectric and electromechanical properties were achieved for a composition close to MPB (0.5 PIN –0.21 PZN –0.29 PT ), where the piezoelectric coefficient d 33 , planar electromechanical coupling factor k p , and remnant polarization P r are 660 pC/N,72%, and 45 μC/cm 2 , respectively. The Curie temperature T C and rhombohedral to tetragonal phase transition temperature T R−T were also derived by temperature dependence of dielectric measurements. The strongly “bended” MPB in the PIN – PT system was found to be “flattened” after addition of PZN in the PIN – PT – PZN system. The results demonstrate a possibility of growing ferroelectric single crystals with high electromechanical properties and expanded range of application temperature.