Metal-Insulator transition induced by post-deposition annealing in low doped manganite films

M. SIRENA; N. HABERKORN; M. GRANADA; L. B. STEREN; J. GUIMPEL

JOURNAL OF APPLIED PHYSICS

American Institute of Physics

Año: 2009 vol. 105 p. 339021 - 339024

0021-8979

We studied the transport and magnetic properties of low-doped manganite films after different oxygenation processes. The oxygen content was adjusted by postdeposition annealing at different oxygen pressures and annealing times. For all the samples we observed an increase in the Curie temperature and the remnant magnetization with the oxygen content. In general, for decreasing number of oxygen vacancies, samples under expansive strain become more homogeneous and their electrical resistivity decreases. A metal-insulator transition is induced in highly oxygenated films grown on SrTiO3, probably related to a shift of the mobility edge crossing below the Fermi energy.We found that the oxygenation dynamics depend critically on the strain field induced by thesubstrates and also on the Sr doping concentration.