ABSTRACTIn this paper, we report our studies on the growth, structural, magnetotransport and magnetic properties of La1−x,CaxMnO3: Co/Ag. Thin films of these materials were grown in situ on (100) LaAlO3 substrates using a pulsed laser deposition technique. Microstructural characterization carried out on these films show that the films are single phase, textured and smooth. The temperature dependence of resistance of the films in the 10 – 300 K range was examined in zero and applied field using four-probe technique and magnetization measurements were carried out using the quantum design superconducting quantum interference device (SQUID) magnetometer. The MR ratios of La0.7Ca0.3MMnO3, Ag added La0.7CaM0.3MnO3 and Co added La0.7CaM0.3MnO3 films were found to be 200%, 3.4 × 104% and 660% in 5 T and 21%, 435% and 30% in 0.1 T respectively. The enhanced MR ratio in the case of Ag added La0.7Ca0.3MMnO3 films is attributed to the increase in the oxygen content and in the case of Co added La0.7Ca0.3MMnO3, it can be attributed to the Co supplying some additional magnetic field.
Meissner state of high-Tc oxide thin films observed by scanning superconducting quantum interference device microscopy