Enhancement of Temperature and Field Coefficient of Resistance in CSD Grown Nanostructure La_0.7Ca_0.3MnO₃ Thin Films

We present the structural, surface and electrical properties of La_0.7Ca_0.3MnO₃ (LCMO) thin films of varying film thicknesses from 150 nm to 300 nm on single crystal LaAlO₃ (LAO) (h00) oriented substrate, prepared using Chemical Solution Deposition (CSD) technique. X-ray diffraction study shows that all LCMO films are epitaxial and (h00) oriented. With increasing film thickness all the films displayed excellent transport properties such as a low resistivity, very high metal-insulator transition temperature (T_P). All the LCMO films show T_P above 275 K. The sharp transition causes highest TCR ~6.10 %/K and FCR ~50 %/T at around room temperature in CSD grown LCMO thin films, which has not been reported so far. A strong dependence of the electrical resistivity and TCR on film thickness is attributed to the oxygen optimization and variation in lattice parameter caused by residual compressive strain of the LCMO films.