Penetration depth and absorption mechanisms of spin currents in Ir$_{80}$Mn$_{20}$ and Fe$_{50}$Mn$_{50}$ polycrystalline films by ferromagnetic resonance and spin pumping

Spintronics relies on the spin dependent transport properties of ferromagnets (F). Although antiferromagnets (AF) are used for their magnetic properties only, some fundamental F-spintronics phenomena like spin transfer torque, domain wall motion and tunnel anisotropic magnetoresistance also occur with AF, thus making AF-spintronics attractive. Here, room temperature penetration depths of spin currents in Ir$_{80}$Mn$_{20}$ and Fe$_{50}$Mn$_{50}$ are determined by F-resonance and spin pumping. We find unlike values in these AF, originating from different absorption mechanisms: dephasing and spin flipping.