Characteristics of La–Ba–Mn–O thin films grown by metal-organic decomposition

La0.67Ba0.33MnOz thin films were grown by means of metal-organic decomposition MOD.on quartz substrates. Polycrystalline structure of the films withw202xpreferred orientation was shown by X-ray diffraction spectrum. Atomic force microscope images revealed that the films were smoothly grown on the substrates and structural defects such as porosity were displayed in the films. The chemical states of the elements obtained from X-ray photoemission spectra were discussed in detail and oxygen deficiency was observed. Furthermore, the magnetic property and magnetotransport behavior of the films were investigated. The films showed a low ferromagnetic transition temperature Tc.of about 265 K due to the oxygen deficiency. A smooth metal–insulator transition peaking at a temperature far below Tc presented in the temperature dependence of resistivity under zero field. No magnetoresistance MR.peak but an enhanced MR effect at low temperature was observed under 10 kOe field. The above magnetotransport behavior was ascribed to the structural defects such as grain boundaries and porosity in the films. q2000 Elsevier Science B.V. All rights reserved