Transport and magnetic properties of DC-magnetron sputterred Ln(0.7)Mn(1.3) O3-delta thin films

Epitaxial thin films of Ln(0.7)Mn(1.3)O(3-delta) have been grown on [0 0 1] -oriented LaSrAlO4 substrates by DC-magnetron deposition. Magnetization, re sistivity, thermopower, and magnetic resonance spectra are investigated ove r a range of temperatures and magnetic fields. The magnetic polaron theory is used, phenomenologically, to provide a quantitative explanation of trans port properties of the oxidized films both above and below Curie temperatur e T-C. The main assumption is that metal-insulator transition near T-C is d ue to a crossover in polaronic mobility. At low temperatures we observe an anisotropy of magnetic resonance spectra, both resonance field and linewidt h. To qualitatively account for all the observations (resistivity, thermopo wer, and magnetic resonance spectra) we suggest an intrinsic electric and m agnetic inhomogeneity of the samples. (C) 1999 Elsevier Science B.V. All ri ghts reserved.