Growth, structural characteristics and magnetoresistance in La-Ca-Mn-O thin films prepared by dc magnetron sputtering

Colossal magnetoresistive (CMR) La-Ca-Mn-O thin films have been successfully fabricated by de magnetron sputtering technique onto heated single crystal substrates such as LaAlO3(001) (LAO), SrTiO3(001) (STO), NdGaO3(110) (NGO) and ZrO2(001) (ZRO). The X-ray diffraction (XRD) patterns showed that the films deposited on LAG, STO and NGO substrates grow epitaxially (001) with FWHM (Delta W) less than 0.5 degrees due to excellent lattice matching and compatible coefficients of thermal expansion between the substrate and the thin film. Those deposited on ZRO preferred to grow (001) texture orientation due to large mismatching of their lattice constants, and Delta W is about 10 degrees. The magnetoresistance measurements show that all of these films exhibit remarkable CMR effect, but the temperature dependence of magnetoresistance in LCMO thin films strongly depend on substrates. These differences are associated with the different temperature dependence of magnetization due to their intrinsic structural characteristics. (C) 1997 Elsevier Science S.A.