Terahertz auto oscillations in non-collinear coplanar metallic antiferromagnets

Owing to their nonlinear dynamics, frequency tunability, nanoscale size, and the ability to operate over broad temperatures, spin torque-driven ferromagnet (FM)-based oscillators are excellent candidates for various neuromorphic computing applications [1]. However, FM oscillators operate at gigahertz speed, which limits the net throughput of the architecture. Antiferromagnet (AFM)-based oscillators can operate at terahertz (THz) frequency due to a strong exchange interaction [2], and thus help overcome the limits of FM oscillators for neuromorphic computing. Also, the dynamics of AFMs can be tuned to display coherent rotation as well as non-coherent spikes [4], which have a similarity to the dynamics of neurons. Prior works have focused on the dynamics in collinear AFMs, such as NiO [2], [3], [4], while that in non-collinear AFMs is virtually unexplored even though their larger magnetoresistance and anomalous Hall effects should enable efficient detection. Here, we report a numerical analysis of the THz dynamics of non-collinear coplanar conducting AFMs such as Mn
₃
Ir and Mn
₃
Sn and compare their performance to that of NiO. Unlike NiO, the oscillations of the order parameter in metallic AFMs studied here are transduced into voltage signal using the tunnel anisotropy magnetoresistance (TAMR) measurement [6].