Enhanced Dielectric Response and Sensing Performance of Bi₂MnCoO₆/BaTiO₃ Composites for Temperature Sensing Application

Dielectric ceramics are proven and promising candidates for capacitive temperature sensor application due to their great sensitivity and linearity over a defined temperature range. The sensor is appropriate for applications that require high accuracies in a narrow temperature range, such as biomedicine, food safety, and food processing. In this study, we have synthesized the composites ( $1-{x}{)}$ Bi2MnCoO6-( ${x}{)}$ BaTiO3 consisting of two individual phases where ${x}$ = 0, 0.02, 0.06, and 0.10 were prepared by a solid-state reaction method. The surface morphology of ( $1-{x}{)}$ Bi2MnCoO6-( ${x}{)}$ BaTiO3 ceramics has been studied using field emission scanning electron microscope (FESEM) micrographs and found enhancement in the average grain size with the addition of BaTiO3. The dielectric spectroscopy revealed that as the temperature increases, there is an increase in dielectric constant, and all the samples exhibit frequency-dependent relaxor ferroelectric (RFE) behavior with a broad peak at curie temperature due to diffusive phase transition. There is also a significant increase in the dielectric constant and a decrease in the dielectric loss of ( $1-{x}{)}$ Bi2MnCoO6-( ${x}{)}$ BaTiO3 ceramics observed with an increase in BaTiO3 concentration due to excellent dielectric properties of BaTiO3. As the capacitance is directly proportional to the material’s dielectric constant, there is also an increase in the sensing property of the sensor. From the measured data, the sensitivity of ( $1-{x}{)}$ Bi2MnCoO6-( ${x}{)}$ BaTiO3 composites are 1.21, 3.01, 5.63, and 6.26 pF/°C. Among all the composites, the ${x}$ = 0.10 composite shows the highest sensitivity and linear response in the desired ambient temperature range.