Inter- and Intrasublattice Spin Mixing Conductance of the Antiferromagnetic Spin Pumping Effect in α−Fe2O3/Pt

The spin pumping effect in antiferromagnets, which ultimately converts THz waves into a spin current, is the key physical mechanism leading to an essential function which harnesses the THz technology and spintronics. Here, we report thorough experimental investigations of the spin current induced by the antiferromagnetic spin pumping effect in epitaxial $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ thin films having two distinct dynamic modes and unambiguously show that both the inter- and intrasublattice spin mixing conductance are equally substantial. Our experimental insight is an important advance for understanding the physics of transduction between the spin current and the staggered magnetization dynamics at THz frequency.