Revealing the importance of interfaces for pure spin current transport

TL;DR

This study investigates how interface quality affects pure spin current transport in spintronic devices, revealing that fabrication methods significantly influence spin Hall signals and absorption, with interface imaging correlating these effects.

Contribution

It demonstrates the critical role of interface quality in spin transport and introduces a method to directly image interfaces to understand their impact.

Findings

Interface quality varies with fabrication method.

Spin Hall effect signals depend on interface properties.

Imaging reveals correlation between interface quality and spin transport.

Abstract

Spin transport phenomena underpin an extensive range of spintronic effects. In particular spin transport across interfaces occurs in most device concepts, but is so far poorly understood. As interface properties strongly impact spin transport, one needs to characterize and correlate them to the fabrication method. Here we investigate pure spin current transport across interfaces and connect this with imaging of the interfaces. We study the detection of pure spin currents via the inverse spin Hall effect in Pt and the related spin current absorption by Pt in Py-Cu-Pt lateral spin valves. Depending on the fabrication process, we either find a large (inverse) spin Hall effect signal and low spin absorption by Pt or vice versa. We explain these counter-intuitive results by the fabrication induced varying quality of the Cu/Pt interfaces, which is directly revealed via a special scanning electron microscopy technique for interface imaging and correlated to the spin transport.