Anomalous spin-orbit field via Rashba-Edelstein effect at W/Pt interface

TL;DR

This study demonstrates that the W/Pt interface generates an additional spin-orbit field in a trilayer structure through the Rashba-Edelstein effect, enabling control of spin-orbit interactions beyond the ferromagnet/metal interface.

Contribution

It reveals a new mechanism for generating and controlling spin-orbit fields via interface effects in multilayer structures.

Findings

W/Pt interface produces an extra spin-orbit field

The field arises from Rashba-Edelstein effect and spin transport

Control of the field strength is possible by combining metals

Abstract

We have studied spin-orbit (SO) field in Ni$_{80}$Fe$_{20}$(Py)/W/Pt trilayer by means of spin-torque ferromagnetic resonance, and demonstrated that the W/Pt interface generates an extra SO field acting on the Py layer. This unprecedented field originates from the following three processes, 1) spin accumulation at W/Pt interface via the Rashba-Edelstein effect, 2) diffusive spin transport in the W layer, and 3) spin absorption into the Py layer through accumulation at the Py/W interface. Our result means that we can create extra SO field away from the ferromagnet/ metal interface and control its strength by a combination of two different metals.