Femtosecond control of electric currents at the interfaces of metallic ferromagnetic heterostructures

TL;DR

This paper demonstrates the ultrafast generation and control of spin-polarized electric currents at ferromagnetic interfaces using femtosecond laser pulses, advancing spintronics into the terahertz frequency range.

Contribution

It introduces a method to optically generate and control spin-polarized currents at femtosecond timescales in metallic heterostructures, enabling ultrafast spintronic applications.

Findings

Optical generation of spin-polarized currents at femtosecond timescale.

Control of photocurrent direction via light helicity.

Potential for terahertz regime spintronics.

Abstract

The idea to utilize not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10$^{12}$ Hz) emission spectroscopy, we demonstrate optical generation of spin-polarized electric currents at the interfaces of metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.