Tuning strain-stress and electron-lattice effects to enhance electrical transport properties of La0.7Ca0.25K0.05MnO3 films via optimizing sintering temperatures

Facile-prepared films with a high-temperature coefficient of resistivity ( TCR ) are crucial for application in high-sensitivity bolometers. In this study, La 0.7 Ca 0.25 K 0.05 MnO 3 (LCKMO) films were grown on (001)-oriented La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 (LSAT) substrates using the spin-coating method. Various sintering temperatures (900 °C ≤  T s  ≤ 1050 °C) were utilized in the film preparation, causing the lattice mismatch between films and substrate degraded. The effect of T s on the strain state of films was investigated through X-ray diffraction (XRD) analysis. The distortion of MnO 6 octahedra and the Mn–O bond were assessed using Raman and FTIR spectra, respectively. The structural perfection and elemental valence of films were adjusted via optimizing T s . Meanwhile, the strain state and defect structure were effectively improved with T s increasing. These results indicate that the LCKMO films with high crystalline quality can be achieved by optimizing the sintering process. The TCR of LCKMO films was modified. When T s at 1000 °C, the LCKMO films exhibit the remarkable TCR of 16.29% K -1 at 269.54 K, indicating the substantial potential of LCKMO films in infrared bolometers.