Superconductivity in epitaxial thin films of Fe_1.08Te:O _x

Superconducting thin films of Fe_1.08Te:O_x have been epitaxially grown on SrTiO₃ substrates by pulsed-laser deposition in controlled oxygen atmosphere. Although the bulk Fe_1.08 Te is not superconducting, thin films with oxygen are superconducting with an onset and a zero resistance transition temperature around 12 and 8 K, respectively. Oxygen was found to be crucial to the superconducting properties of these films, suggesting that the oxygen incorporation can induce superconductivity in FeTe thin films. A metal-insulator transition is found at about 60 K, lower than that of bulk (∼70 K). From magnetoresistive measurements, we obtained the irreversibility line and the upper critical field.