Journal of Crystal Growth, Vol.454, 134-138, 2016
Lithium outdiffusion in LiTi2O4 thin films grown by pulsed laser deposition
We report surface chemical cation composition analysis of high quality superconducting LiTi2O4 thin films, grown epitaxially on MgAl2O4 (111) substrates by pulsed laser deposition. The superconducting transition temperature of the films was similar to 13.8 K. Surface chemical composition is crucial for the formation of a good metal/insulator interface for integrating LiTi2O4 into full-oxide spin-filtering devices in order to minimize the formation of structural defects and increase the spin polarisation efficiency. In consideration of this, we report a detailed angle resolved x-ray photoelectron spectroscopy analysis. Results show Li segregation at the surface of LiTi2O4 films. We attribute this process due to outdiffusion of Li toward the outermost LiTi2O4 layers. (C) 2016 The Authors. Published by Elsevier B.V.
Keywords:Physical vapor deposition processes;Oxides;Lithium compounds;Titanium compounds;Oxide superconducting materials