La0.7Ca0.3MnO3-:Ag nanocomposite thin films with large temperature coefficient of resistance (TCR)

In this work, oxygen vacancy-regulated La0.7Ca0.3MnO3-δ:Ag (LCMO:A) nanocomposite thin films on LaAlO3 (001) substrates were investigated to obtain films with large temperature coefficient of resistance (TCR) values. LCMO:A nanocomposite thin films were synthesized using pulsed laser deposition, and oxygen pressures during film deposition and annealing steps were optimized. As oxygen pressures increased, lattice parameter increased from 70 Pa to 100 Pa, Tp increased monotonically from 168 K to 282 K, and average Mn4+ concentration in the film increased as indicated by X-ray photoemission spectroscopy data. Record high TCR value of ∼37% K−1 was achieved in LCMO:A nanocomposite thin film prepared with optimal oxygen pressures, making this film promising candidate for applications in bolometers.