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

A new type of BiMeO3-PbTiO3 was prepared by using Li1+ as part of the Me site cations. Several (1-x)Bi(Li,Me '')O-3-xPbTiO(3) compositions were prepared with Me '' cations of a higher valence (Me '' = Ti4+, Zr4+, Mn4+, Sn4+, Nb5+, and Ta5+). (1-x)Bi(Li,Me '')O-3-xPbTiO(3) exhibits a low solubility of Bi(Li,Me '')O-3 in PbTiO3. Although there are many possible compositions of (1-x)Bi(Li,Me '')O-3-xPbTiO(3), no morphotropic phase boundary was found. After the initial screening, (1-x)Bi(Li1/3Zr2/3)O-3-xPbTiO(3) 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)O-3-xPbTiO(3). The temperature dependence of 0.3Bi(Li1/3Zr2/3)O-3-0.7PbTiO(3) and 0.3(Bi0.9La0.1)(Li1/3Zr2/3)O-3-0.7PbTiO(3) was assessed by investigating the dielectric constant epsilon(T)(33)) and large-signal d(33). 0.3Bi(Li1/3Zr2/3)O-3-0.7PbTiO(3) exhibits a dielectric constant (epsilon(T)(33) = 504) with a low loss (0.025), ferroelectric properties (E-C = 5.9 kV/mm, P-r = 20.8 mu C/cm(2), and P-sat = 25.9 mu C/cm(2)), piezoelectric coefficients (small-signal d(33) = 78 pC/N and large-signal d(33) = 106 pm/V), and Curie temperature (T-C = 290 degrees C). La (10 mol%) substitution for Bi acts as a soft role with an enhanced d(33) (98 pC/N) and reduced T-C (215 degrees C).