Advancements in Capacitive Temperature Sensing through Bi₂MnCoO₆ and Bi_0.5Na_0.5TiO₃ Integration

Developing capacitive temperature sensors with high accuracy necessitates identifying materials that not only exhibit substantial temperature-induced capacitance changes (high dC/dT values) but also maintain a linear capacitance-temperature relationship. This combination ensures precise and consistent temperature measurements across varying conditions. Among relaxor ferroelectric, Bi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>MnCoO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> is recognized for its nearly linear behavior, whereas Bi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>Na<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>TiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> demonstrates high dC/dT values and a broad operational range. Combining these two materials offers a promising strategy to achieve both linearity and enhanced sensitivity in temperature sensing applications. In this current work, we synthesized composites of Bi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>MnCoO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> / Bi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>Na<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>TiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> composite using the solid-state reaction method to develop capacitive temperature sensors with enhanced sensitivity and an extended operational temperature range, aiming to leverage the synergistic effects of both components. Structural analyses confirmed the formation of phase-pure materials, and microstructural evaluations revealed well-developed grains, with the BMCO/BNT composite exhibiting a larger average grain size compared to pure BMCO. Dielectric spectroscopy demonstrated that the BMCO/BNT composite possesses a nearly linear capacitance-temperature response, achieving a sensitivity of 3.71 pF/°C and a relative sensitivity of 7.27%/°C over a broad temperature range of 30°C to 330°C. This marks a significant enhancement over pure BMCO, which exhibited a sensitivity of 0.77 pF/°C within a narrower temperature range. The improved sensitivity and linearity of the BMCO/BNT composite highlight its potential as a high-performance material for capacitive temperature sensors, offering promising applications in industrial and biomedical fields requiring precise and reliable temperature measurements.