Taming the resistive switching in Fe/MgO/V/Fe magnetic tunnel junctions: An ab initio study

A possible mechanism for the resistive switching observed experimentally in Fe/MgO/V/Fe junctions is presented. Ab initio total energy calculations within the local density approximation and pseudopotential theory shows that by moving the oxygen ions across the MgO/V interface one obtains a metastable state. It is argued that this state can be reached by applying an electric field across the interface. In addition, the ground state and the metastable state show different electric conductances. The latter results are discussed in terms of the changes of the density of states at the Fermi level and the charge transfer at the interface due to the oxygen ion motion. •Local minima are found for oxygen near the interface with at least one oxygen moved.•Relaxation of a small unit cell preserves this result and lowers energy barrier.•V on the top of Mg exhibits the minimum and a reasonable energy barrier.•Sense of switching: experimental evidence of the configuration (V on O or V on Mg).•Sense of switching can be understood in terms of charge oscillations induced by the O.