Modulation of synchronization in spin hall nano-oscillators

Abstract

Spin-orbit coupling, a phenomenon that enables the generation of nonlocal spin currents using nonmagnetic materials, is actively researched in the field of spintronics to facilitate the miniaturization and reduction of power consumption in conventional electronic devices. Recent efforts have focused on exploring spin-orbit coupling at the interface of nonmagnetic and ferromagnetic materials, aiming to implement magnetic reversal or spin-torque oscillators. However, many studies have been limited to nonmagnetic/ferromagnetic single-junction structures, underscoring the need for investigations into more complex structures. Here, this paper explores synchronization phenomena in spin-orbit torque-based nano-oscillators featuring nonmagnetic /ferromagnetic junction structures. Examining synchronization dependencies on number of spin Hall nano-oscillators (SHNOs) and distance, as well as synchronization via external radio frequencies, the objective is to advance comprehension and broaden the utility of SHNOs. Through an investigation into synchronization phenomena in nanoscale oscillators, enhancements in Q-factor and output performance indicative of wireless frequency characteristics are observed. Furthermore, by synchronizing with external frequencies, the application of GHz-range spin Hall nano-oscillators in realizing the attributes of an Ising machine is validated, thereby advancing understanding and expanding the scope of spin Hall nano-oscillator applications.