THz-Frequency Signal Sources Based on Antiferromagnetic Spin Hall Oscillators

It was recently shown that an antiferromagnetic (AFM) spin Hall oscillators (SHOs) consisting a thin AFM layer covered by a current-driven thin metal layer having a strong spin-orbital coupling can be used as a micro- and nano-scale sources of 0.1 - 3 THz-frequency electromagnetic signals. However the problem of ac signal power extraction from an AFM SHO is not solved yet, which greatly limits applications of such signal sources. In this paper we theoretically analyze and compare performance of AFM-based THz-frequency signal sources, where ac signal power is extracted via the direct magnetic dipole emission and THz-frequency variations of the tunneling anisotropic magnetoresistance (TAMR) in AFM tunnel junction. Our calculations show that the mechanism of magnetic dipole emission could provide rather high output ac power (similar to 1-10 mu W) in the frequency range 0.5 - 1 THz, while the second method utilizing the TAMR is more convenient for experimental realization at micro- and nano-scale.