Hysteresis loops in the current-voltage characteristics of magnetic tunneljunctions

An experimental study on the electric conduction of magnetic tunnel junctio ns is presented. The junctions comprise two ferromagnetic-metal films and a n ultrathin nonmagnetic dielectric interlayer. The fabrication technique ar e described. The current through a junction is measured versus the voltage applied to the junction. It is found that the current-voltage characteristi cs may have loops, which may be complicated in shape and irreproducible. Th is 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 explanatio n are discussed. It is demonstrated that the hysteresis loops and the irrep roducibility can be suppressed in a sufficiently strong external magnetic f ield.