High temperature properties of manganese modified CaBi₄Ti₄O₁₅ ferroelectric ceramics

The dielectric, piezoelectric and electromechanical properties of manganese modified CaBi₄Ti₄O₁₅ (CBT) bismuth layer-structured ferroelectric ceramics were determined in the range of room temperature to ∼800 ^{{ring operator}}C. The room temperature dielectric permittivity and dielectric loss were found to be 148 and 0.2%, respectively. The piezoelectric coefficients, d₃₃ and d₁₅, were 14  pC/N and 9  pC/N, with electromechanical coupling factors k₃₃^′ = 8.4 % and k₁₅ = 5.5 %. The mechanical quality factor Q (sliver extensional mode) was 4300 at room temperature, decreasing with increasing temperature. The remnant polarization and coercive field were found to be 5.2 μC/cm² and 88 kV/cm, respectively. The excellent piezoelectric, mechanical properties, together with its high Curie temperature (∼800 ^{{ring operator}}C) and high electrical resistivity (1 × 10⁷ Ω cm at 500 ^{{ring operator}}C), demonstrated the potential of manganese modified CBT ceramics for ultra-high temperature sensing applications.