Microstructure and Electrical Properties of (1−x)Bi(Li1/3Zr2/3)O3–xPbTiO3 Piezoelectric Ceramics

Abstract

A new type of BiMeO3–PbTiO3 was prepared by using Li1+ as part of the Me site cations. Several (1−x)Bi(Li,Me″)O3–xPbTiO3 compositions were prepared with Me″ cations of a higher valence (Me″=Ti4+, Zr4+, Mn4+, Sn4+, Nb5+, and Ta5+). (1−x)Bi(Li,Me″)O3–xPbTiO3 exhibits a low solubility of Bi(Li,Me″)O3 in PbTiO3. Although there are many possible compositions of (1−x)Bi(Li,Me″)O3–xPbTiO3, no morphotropic phase boundary was found. After the initial screening, (1−x)Bi(Li1/3Zr2/3)O3–xPbTiO3 was identified as the most promising material for actuator applications due to its relatively large solubility limit (x=0.7) and low lattice distortion (c/a=1.036). It was then chosen for systematical study with respect to structure, ferroelectric, and piezoelectric properties. In addition, La was further added to improve the piezoelectric properties of (1−x)Bi(Li1/3Zr2/3)O3–xPbTiO3. The temperature dependence of 0.3Bi(Li1/3Zr2/3)O3−0.7PbTiO3 and 0.3(Bi0.9La0.1)(Li1/3Zr2/3)O3−0.7PbTiO3 was assessed by investigating the dielectric constant and large‐signal d33. 0.3Bi(Li1/3Zr2/3)O3−0.7PbTiO3 exhibits a dielectric constant with a low loss (0.025), ferroelectric properties (EC=5.9 kV/mm, Pr=20.8 μC/cm2, and Psat=25.9 μC/cm2), piezoelectric coefficients (small‐signal d33=78 pC/N and large‐signal d33=106 pm/V), and Curie temperature (TC=290°C). La (10 mol%) substitution for Bi acts as a soft role with an enhanced d33 (98 pC/N) and reduced TC (215°C).