Locking of magnetic moment precession in a nanomagnet coupled to a Josephson junction under external radiation

We investigate the<i>IV</i>curve and magnetic moment amplitude in a coupled system consisting of a single-domain nanomagnet and Josephson junction (JJ) driven by external electromagnetic radiation. The role of the magnetic field generated by the quasiparticle current on the locking of magnetic moment precession and Josephson oscillations is demonstrated. It leads to the appearance of a bubble-like structure in the bias current dependence of the maximal amplitude of magnetic moment. This bubble feature corresponds to the locking of magnetic precession by external radiation, analogous to the well-known Shapiro steps in the<i>IV</i>curve of JJs. The locking properties in the system can be controlled through parameters of the external signal, such as frequency and amplitude. These findings enable the control of magnetic precession through external radiation in Josephson hybrid structures, which can be useful for applications in superconducting spintronics.