Critical role of interface states for spin-dependent tunneling in half-metallic Co2MnSi-based magnetic tunnel junctions investigated by tunneling spectroscopy

We investigated at 4.2 K the differential conductance (dI/dV) versus V characteristics of fully epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions (MTJs) featuring high tunnel magnetoresistance ratios of about 700% at 4.2 K (about 180% at room temperature). We developed a tunneling model to explain the observed tunneling spectra and showed the critical role played by interface states for minority spins existing around the Fermi level of Co2MnSi electrodes facing a MgO tunnel barrier in the spin-dependent tunneling characteristics of these MTJs with half-metallic electrodes.