Josephson Current Induced by Ferromagnetic Resonance

摘要

We proposed the Josephson effect induced by spin waves in a Ferromagnetic Josephson junction, in which two superconductors are separated by a ferromagnetic thin layer[1]. The phenomenological model of the superconducting phase dynamics is extended to include the spin wave excitation induced by ferromagnetic resonance (FMR). The current-voltage characteristics show step structures if the microwave frequency coincides with the FMR. Our results show a new route to observe the spin wave excitation using the Josephson effect. The Josephson effect is characterized by the zero voltage current between two superconductors (SC's) separated by a thin insulating barrier as shown in Fig. 1. This effect is a macroscopic quantum phenomenon induced by phase coherence between two superconductors. When a finite voltage-drop (V) appears in the junction, the phase difference (0) evolves with time. As a result, an alternating current flows due to the time dependence of 6. When an alternating electric field by microwave irradiation is applied to the junction, the current-voltage (I-V) characteristics become like as a staircase, that is called Shapiro step.