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DOE OSTI · 1852549

Femtosecond photocurrents at the FeRh/Pt interface

Medapalli, R.·Li, G.·Patel, Sheena K. K.·Mikhaylovskiy, R. V.·Rasing, Th.·Kimel, A. V.·Fullerton, E. E.
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Abstract

Femtosecond laser excitations of FeRh/Pt bilayers launch an ultrafast pulse of electric photocurrents in the Pt-layer and subsequently result in the emission of electromagnetic radiation in the THz spectral range. Analysis of the THz emission as a function of the polarization of the femtosecond laser pulse, external magnetic field, sample temperature, and sample orientation shows that the photocurrent can emerge due to vertical spin pumping and photo-induced inverse spin–orbit torque at the FeRh/Pt interface. Additionally, the vertical spin pumping from FeRh into Pt does not depend on the polarization of light and originates from ultrafast laser-induced demagnetization of the ferromagnetic phase of FeRh. The photo-induced inverse spin–orbit torque at the FeRh/Pt interface can be described in terms of a helicity-dependent effect of circularly polarized light on the magnetization of the ferromagnetic FeRh and the subsequent generation of a photocurrent.

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Medapalli, R., Li, G., Patel, Sheena K. K., Mikhaylovskiy, R. V., Rasing, Th., Kimel, A. V., Fullerton, E. E.. 2020-10-05. Femtosecond photocurrents at the FeRh/Pt interface. https://doi.org/10.1063/5.0026252

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