Room-temperature generation of giant pure spin currents using Co$_2$FeSi spin injectors

TL;DR

This paper demonstrates that using Co$_2$FeSi Heusler-compound spin injectors in lateral spin valve devices significantly enhances pure spin current generation efficiency at room temperature, advancing spintronic technology.

Contribution

It introduces the use of highly ordered Co$_2$FeSi Heusler compounds as efficient spin injectors, achieving a hundredfold increase in pure spin current generation over conventional materials.

Findings

Pure spin currents generated at room temperature with Co$_2$FeSi injectors.

Generation efficiency is approximately 100 times higher than NiFe.

Heusler compounds show great potential for high-performance spintronic devices.

Abstract

Generation, manipulation, and detection of a pure spin current, i.e., the flow of spin angular momentum without a charge current, are prospective approaches for realizing next-generation spintronic devices with ultra low electric power consumptions. Conventional ferromagnetic electrodes such as Co and NiFe have so far been utilized as a spin injector for generating the pure spin currents in nonmagnetic channels. However, the generation efficiency of the pure spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here, we demonstrate the generation of giant pure spin currents at room temperature in lateral spin valve devices with a highly ordered Heusler-compound Co$_2$FeSi spin injector. The generation efficiency of the pure spin currents for the Co$_2$FeSi spin injectors reaches approximately one hundred times as large as that for NiFe ones, indicating that Heusler-compound spin injectors enable us to materialize a high-performance lateral spin device. The present study is a technological jump in spintronics and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating pure spin currents.