Modulation, Injection Locking, and Pulling in an Antiferromagnetic Spin-Orbit Torque Oscillator

Antiferromagnets (AFMs) can extend the working frequency of spintronics to terahertz range while using similar geometries and concepts of gigahertz ferromagnet-based spintronic devices. Here, we investigate micromagnetically the dynamics of spin-Hall oscillators driven by the simultaneous action of a dc and an ac current. Our findings include the clear occurrence of three types of dynamics, depending on the frequency of the ac with respect to the self-oscillation frequency excited by the dc: 1) frequency modulation; 2) frequency pulling; and 3) injection locking. These results confirm the suitability of AFMs for the development of a terahertz technology which can impact the field of telecommunications.