Spin-current related terahertz emission from the Co/Pt heterostructure

The terahertz emission based on the spin current in the ferromagnetic heterostructure Co/Pt is demonstrated. The polarity reversal of the terahertz waveforms when the magnetization direction or the sample orientation was changed proved that the spin current was responsible to the THz emission from Co/Pt heterostructures. The Pt-layer-thickness dependence of the terahertz emission amplitude is investigated. The model including the effect of the spin current transport in the bulk material and the spin memory loss on the interface quantitatively explains the impact of the layer-thickness on the terahertz emission from the ferromagnetic heterostructure.