Optimization of the electrical transport properties of La0.7Ca0.3MnO3 films by sintering temperature adjustment

With the development of the radiation thermometers, perovskite manganites have been fallen into the focus of highly sensitive infrared bolometers due to its metal-insulator transition properties. In this study, La0.7Ca0.3MnO3 (LCMO) films were prepared on (l00) LaAlO3 substrates using sol-gel spin-coating technology by adjusting different sintering temperatures (Ts, 1000 °C ≤ Ts ≤ 1400 °C). The analysis of the microstructure, surface morphology, ion valence state, and electrical transport properties revealed that the crystalline quality enhanced and the concentration of Mn4+ increased with the increasing of sintering temperature, promoting the DE effect and improving the electrical properties of the LCMO films. At Ts = 1200 °C, the temperature coefficient of resistivity (TCR) value of the LCMO film reached the maximum value (22.95% K−1) and corresponding peak TCR temperature of 246.85 K indicating that the LCMO film has great potential in infrared bolometers.