Transient spin injection efficiencies at ferromagnet/metal interfaces

TL;DR

This paper investigates ultrafast spin injection efficiencies at ferromagnet/metal interfaces using theoretical and experimental methods, revealing how laser and material parameters influence spin injection for potential spintronics applications.

Contribution

It provides a quantitative comparison of ab-initio simulations and experiments to determine spin injection efficiencies and explores how these can be optimized through various parameters.

Findings

Spin injection efficiencies vary with interface properties.

Laser pulse parameters significantly affect spin injection.

Material choice influences the efficiency and optimization.

Abstract

Spin injection across interfaces driven by ultrashort optical pulses on femtosecond timescales constitutes a new way to design spintronics applications. Targeted utilization of this phenomenon requires knowledge of the efficiency of non-equilibrium spin injection. From a quantitative comparison of ab-initio time-dependent density functional theory and interface-sensitive, time-resolved non-linear optical experiment, we determine the spin injection efficiencies (SIE) across ferromagnetic/metal interfaces and discuss their microscopic origin, i.e. the influence of spin-orbit coupling and the interface electronic structure. Moreover, we find that the SIE can be optimized through laser pulse and materials parameters, namely the fluence, pulse duration, and substrate material.