Increasing the Efficiency of Terahertz Generation during the Current Flow through Magnetic Junctions Formed by Inhomogeneous Ultrathin Films of a Ferromagnetic Metal

Operating modes of terahertz (THz) generators with “rod–film” magnetic junctions formed by a Fe rod with one pointed end with a diameter of 10–50 nm and various nanometer-thick (single-layer and multilayer) Со films are studied. It is demonstrated that the efficiency of the THz radiation increases (due to an increase in the current density) if the thickness of a single-layer film decreases to the point when it becomes discontinuous (ultrathin) while retains its conductivity. If a multilayer structure with several such films separated by nonmagnetic conductive layers is used, the radiation power can also be increased.