CMR La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 thin films fabricated by sol-gel method

Sol-gel precursors for La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 were made from La, Ca, Sr and Mn acetates with a mixture of 2-ethylhexanoic acid and 2-methexyethanol in a ratio of 2:1 as solvent. With these precursor solutions, La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 thin films were deposited on YSZ and MgO substrates, respectively, by spin coating and sintering at different temperatures. X-ray diffraction (XRD) patterns show that these thin films consist of pure La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 phases. Atomic force microscope images of the thin films show uniformly developed grains and the development of the grains with rising sintering temperature. EDS analysis shows that the composition of grains of La0.7Ca0.3MnO3 thin films is in accordance with the composition of the precursor sol-gel. Magnetization measurements of the fabricated films show typical ferromagnetic order transitions. Conductivity measurements at zero magnetic field show that all the films have typical semiconductor to conductor transitions, and magnetoresistance was demonstrated after a magnetic field was applied. (C) 2004 Elsevier B. V. All rights reserved.