Transport properties of La2/3Sr1/3MnO3/LaAlO3/Pt tunnel junctions

Magnetotransport properties of La2/3Sr1/3MnO3/LaAlO3/Pt tunnel junctions have been thoroughly analyzed, as a function of temperature and magnetic field, to test the suitability of LaAlO3 for insulating barriers and spin injection processes. The insulating behavior of LaAlO3 maintained down to 1-2 nm (corresponding to 4-5 unit cells) renders this material useful as tunnel barrier. The temperature dependence of the junction resistance, R(T), down to 200K confirms direct tunneling as the dominant conduction channel. The barrier parameters of the junctions, phi(0) and s, are estimated using Simmons' model in the intermediate voltage range. The energy of the barrier was estimated to be phi(0) similar to 0.4 eV at room temperature. The dependence of R(T) and phi(0) on the magnetic field shows an anisotropic tunneling magnetoresistance of similar to 4% at low T when changing the direction of the magnetization with respect to the current flow. (C) 2015 AIP Publishing LLC.