The device operation of spin pumping can be regarded as the spintronic analog of a battery.
[1] Spin pumping involves an AC effect and a DC effect: The spin current pumped into an adjacent layer by a precessing magnetic moment is given by[2] where
[6] Since the frequency of antiferromagnetic resonance[7] is much higher than that of ferromagnetic resonance, spin pumping in antiferromagnets can be utilized to study electromagnetic signals in the sub-terahertz and terahertz regime, which had been demonstrated by two independent experiments in 2020.
[8][9] Besides higher frequency, spin pumping in antiferromagnets features the chirality degree of freedom of magnetic dynamics that does not exist in ferromagnets.
For example, the spin currents pumped by the left-handed and the right-handed resonance modes are opposite in direction.