Tuning strain-stress and electron-lattice effects to enhance electrical transport properties of La_0.7Ca_0.25K_0.05MnO₃ 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, La0.7Ca(0.25)K(0.05)MnO(3) (LCKMO) films were grown on (001)-oriented La0.3Sr0.7Al0.65Ta0.35O3 (LSAT) substrates using the spin -coating method. Various sintering temperatures (900 degrees C < T-s < 1050 degrees 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 MnO6 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 degrees 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.