Giant interfacial spin-Hall angle from Rashba-Edelstein effect revealed by the spin-Hall Hanle processes

TL;DR

This paper demonstrates that the Rashba-Edelstein effect at ferroelectric interfaces significantly enhances the interfacial spin Hall angle, revealing a new mechanism for efficient spin-charge conversion in spintronics.

Contribution

It provides experimental evidence of giant interfacial spin Hall angles due to REE at ferroelectric interfaces, using spin-Hall Hanle effects for characterization.

Findings

REE at Pt/ferroelectric interfaces enhances spin Hall angle by three times.

Interfacial spin Hall angle (~0.3) is an order of magnitude larger than bulk Pt.

SHHEs are effective for probing interfacial spin transport properties.

Abstract

The Rashba-Edelstein effect (REE), which generates interfacial spin polarization and subsequent spin current, is a compelling spin-charge conversion mechanism for spintronics applications, since it is not limited by the elemental spin-orbit coupling. In this work, we demonstrate REE at Pt/ferroelectric interfaces using the recently elucidated spin-Hall Hanle effects (SHHE), in which a Larmor precession of spin polarization in a diffusion process from the interface manifest as magnetoresistance and Hall effect. We show that REE leads to a three-fold enhancement of the effective spin Hall angle in ferroelectric interface Pt/h-LuFeO3 compared to that of Pt /Al2O3, although the difference in the spin relaxation time is negligible. Modeling using SHHEs involving REE as an additional source of interfacial polarization suggests that REE can lead to an interfacial spin Hall angle (~0.3) that is one order of magnitude larger than the bulk value of Pt. Our results demonstrate that a ferroelectric interface can produce large spin-charge conversion and that SHHEs are a sensitive tool for characterizing interfacial spin transport properties.