Observation of gigantic orbital mixing conductance

TL;DR

This paper demonstrates that orbital Hall effects can induce significant orbital pumping in materials with weak spin-orbit coupling, leading to a gigantic orbital mixing conductance surpassing traditional spin-mixing conductance.

Contribution

It reveals a new mechanism for orbital current transmission and reports an exceptionally high orbital mixing conductance in Ti/Co interfaces, advancing understanding of orbital transport phenomena.

Findings

Orbital Hall effect induces orbital pumping in weak spin-orbit materials.

Orbital mixing conductance in Ti/Co reaches 474.1 x 10^18 m^(-2), much higher than spin-mixing conductance.

Orbital current transmission across interfaces is more efficient than previously thought.

Abstract

We report that due to the orbital Hall effect, orbital pumping effects can occur in materials with weak spin-orbit coupling. Moreover, there is a positive correlation between the strength of the orbital Hall effect and the size of spin-pumping. During the spin-pumping, with the enhancement of the orbital Hall effect, the resonant absorption of orbital current and the damping of the ferromagnetic layer also increase. Especially, when the thickness of Ti reaches 60 nm, the orbital -mixing conductance of Ti/Co is an order of magnitude higher than spin-mixing conductance of heavy metal/Co, reaching 474.1 3 ^18 m^(-2). The results indicate that the orbital current is more easily transmitted across the interface