Vertical current induced domain wall motion in MgO-based magnetic tunnel junction with low current densities

摘要

Shifting electrically a magnetic domain wall (DW) by the spin transfermechanism is one of the future ways foreseen for the switching of spintronicmemories or registers. The classical geometries where the current is injectedin the plane of the magnetic layers suffer from a poor efficiency of theintrinsic torques acting on the DWs. A way to circumvent this problem is to usevertical current injection. In that case, theoretical calculations attributethe microscopic origin of DW displacements to the out-of-plane (field-like)spin transfer torque. Here we report experiments in which we controllablydisplace a DW in the planar electrode of a magnetic tunnel junction by verticalcurrent injection. Our measurements confirm the major role of the out-of-planespin torque for DW motion, and allow to quantify this term precisely. Theinvolved current densities are about 100 times smaller than the one commonlyobserved with in-plane currents. Step by step resistance switching of themagnetic tunnel junction opens a new way for the realization of spintronicmemristive devices.