Ferrimagnet based spin Hall detector of subterahertz frequency signals

Abstract

A concept of a subterahertz (sub-THz) frequency range signals detector based on a ferrimagnet/normal metal (FiM/NM) heterostructure is proposed. An external linearly polarized electromagnetic (EM) wave excites precession in the FiM and spin pumping at the FiM/NM interface. The excited spin current in the NM converts into a direct current via the inverse spin Hall effect. We show that non-zero uncompensation between magnetic spins in FiM gives a non-zero output rectified voltage for both “easy axis” and “easy plane” uniaxial anisotropies. The increase in the uncompensation parameter removes degeneracy from two normal resonance modes and changes the sensitivity to the EM wave. Namely, the sensitivity of the higher mode increases, and the lower mode decreases with increasing the uncompensation parameter. We believe that our results can be helpful for the practical development of sub-THz frequency tunable resonance detector based on the FiM.