Hysteresis loops in the current-voltage characteristics of magnetic tunnel junctions

An experimental study on the electric conduction of magnetic tunnel junctions is presented. The junctions comprise two ferromagnetic-metal films and an ultrathin nonmagnetic dielectric interlayer. The fabrication technique are described. The current through a junction is measured versus the voltage applied to the junction. It is found that the current-voltage characteristics may have loops, which may be complicated in shape and irreproducible. This effect is interpreted as hysteresis resulting from the influence of the current on the magnetic conditions of the metallic films in the junction, e.g., on their domain system. Experimental results supporting the explanation are discussed. It is demonstrated that the hysteresis loops and the irreproducibility can be suppressed in a sufficiently strong external magnetic field.