Room Temperature Giant Charge-to-Spin Conversion at SrTiO3/LaAlO3 Oxide Interface

TL;DR

This study demonstrates highly efficient room-temperature charge-to-spin conversion at the SrTiO3/LaAlO3 interface, advancing oxide-based spintronic device potential by revealing a significant spin generation mechanism.

Contribution

First demonstration of direct charge-to-spin conversion at the SrTiO3/LaAlO3 interface with high efficiency at room temperature.

Findings

Achieved spin generation efficiency of ~6.3 at room temperature.

Showed spin transmission through LAO layer via inelastic tunneling.

Potential for oxide insulator-based spintronic devices.

Abstract

Two-dimensional electron gas (2DEG) formed at the interface between SrTiO3 (STO) and LaAlO3 (LAO) insulating layer is supposed to possess strong Rashba spin-orbit coupling. To date, the inverse Edelstein effect (i.e. spin-to-charge conversion) in the 2DEG layer is reported. However, the direct effect of charge-to-spin conversion, an essential ingredient for spintronic devices in a current induced spin-orbit torque scheme, has not been demonstrated yet. Here we show, for the first time, a highly efficient spin generation with the efficiency of ~6.3 in the STO/LAO/CoFeB structure at room temperature by using spin torque ferromagnetic resonance. In addition, we suggest that the spin transmission through the LAO layer at high temperature range is attributed to the inelastic tunneling via localized states in the LAO band gap. Our findings may lead to potential applications in the oxide insulator based spintronic devices.