Rectification of the alternating current using DW oscillations in magnetic nanostripes: Numerical simulation studies

Energy of the ambient radio frequency electromagnetic field, which is always present due to the functioning of modern telecommunication devices, can be harvested by converting the ac-current—obtained from suitable antennas—into the dc-current employing a spin-torque diode (STD). Currently, this is a highly important topic by development of possible methods of the green energy production. In this paper, we present the optimal design of such an energy harvester basing on the oscillation of a domain wall (DW) inside a thin magnetic stripe with notches confining the displacement of this wall. First, we derive the maximal achievable conversion efficiency of a STD-based harvester. Afterward we show that among various designs of these devices, the highest efficiency (about 75% of the possible maximum) is obtained by using the oscillation of an out-of-plane DW confined in a stripe between two rectangular notches. Hence, we expect that this design open new perspectives for tunable spintronic rectifiers to be used as energy-harvesting elements in nanoscale devices.