Competing spin transfer and dissipation at Co/Cu(001) interfaces on femtosecond timescales

TL;DR

This study combines advanced experiments and theory to reveal how ultrafast spin transfer and dissipation occur at Co/Cu(001) interfaces within femtoseconds, highlighting fundamental microscopic processes relevant for spintronic devices.

Contribution

It provides a detailed microscopic understanding of competing spin transfer and dissipation processes at ferromagnetic interfaces on femtosecond timescales.

Findings

Spin-dependent charge transfer occurs within 100 fs.

Spin-orbit coupling mediates spin dissipation.

Ultrafast spin dynamics are characterized at Co/Cu interfaces.

Abstract

By combining interface-sensitive non-linear magneto-optical experiments with femtosecond time resolution and ab-initio time-dependent density functional theory, we show that optically excited spin dynamics at Co/Cu(001) interfaces proceeds via spin-dependent charge transfer and backtransfer between Co and Cu. This ultrafast spin transfer competes with dissipation of spin angular momentum mediated by spin-orbit coupling already on sub 100 fs timescales. We thereby identify the fundamental microscopic processes during laser-induced spin transfer at a model interface for technologically relevant ferromagnetic heterostructures.