Manganese-modified BiScO3–PbTiO3 piezoelectric ceramic for high-temperature shear mode sensor

The bismuth-based perovskite solid solution $(100-x)\mathrm{Bi}\mathrm{Sc}{\mathrm{O}}_3-x\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_3$ (BSPT) was investigated for use at temperatures up to $400°\mathrm{C}$ and above. The high-temperature resistivity, together with dielectric and piezoelectric behaviors of the shear mode for manganese-modified BSPT ceramics near the morphotropic phase boundary composition were studied. The resistivity and time constant were found to be $3\times {10}^7\Omega \mathrm{cm}$ and $0.08\mathrm{s}$ , respectively, at $450°\mathrm{C}$ for modified BSPT66. The dielectric constant ${{\rm K}}_{11}^T$ and dielectric loss were found to be 1112 and 1%, respectively, at room temperature, showing a Curie temperature at $468°\mathrm{C}$ . The electromechanical coupling factor $k_{15}$ was calculated to be 61%, staying nearly constant up to $440°\mathrm{C}$ , expanding the temperature usage range significantly. The properties indicate that the modified BSPT66 material is a promising candidate for high-temperature shear sensor applications.