All-electrical spin-to-charge conversion in sputtered Bi$_x$Se$_{1-x}$

TL;DR

This paper demonstrates all-electrical spin-to-charge conversion in Bi$_x$Se$_{1-x}$ nanodevices and highlights how contact intermixing can significantly affect efficiency estimates, impacting spintronic device development.

Contribution

It reveals the impact of intermixing at contacts on spin-to-charge conversion efficiency in Bi$_x$Se$_{1-x}$, providing insights for improving spintronic device performance.

Findings

Conversion efficiency can be overestimated by tens of times due to contact intermixing.

Intermixing causes compositional changes affecting resistivity and spin Hall angle.

Strategies to enhance spin-to-charge conversion signals are discussed.

Abstract

One of the major obstacles to realizing spintronic devices such as MESO logic devices is the small signal magnitude used for magnetization readout, making it important to find materials with high spin-to-charge conversion efficiency. Although intermixing at the junction of two materials is a widely occurring phenomenon, its influence on material characterization and the estimation of spin-to-charge conversion efficiencies is easily neglected or underestimated. Here, we demonstrate all electrical spin-to-charge conversion in Bi$_x$Se$_{1-x}$ nanodevices and show how the conversion efficiency can be overestimated by tens of times depending on the adjacent metal used as a contact. We attribute this to the intermixing-induced compositional change and the properties of a polycrystal that lead to drastic changes in resistivity and spin Hall angle. Strategies to improve the spin-to-charge conversion signal in similar structures for functional devices are discussed.