High quality SrTiO3 tunnel barrier obtained by pulsed laser deposition

The quality of a SrTiO3 tunnel barrier deposited by pulsed laser deposition on SrTiO3 (001)‖Sr2FeMoO6 is investigated. Epitaxy and two-dimensional growth are obtained and the root-mean-square roughness is 0.3nm. The distribution of the local current measured by conductive atomic force microscopy indicates that hot spots are almost absent. The standard deviation of the barrier thickness distribution is lower than 0.05nm. Current-voltage characteristics of patterned magnetic tunnel junctions provide evidence of the high quality of the barrier. The electrical properties of the SrTiO3 barrier are at least as good as the ones obtained by sputtering or e-beam evaporation.