A schematic showing the conversion of charge current to spin current based on the spin Hall effect in Co3Sn2S2. Image: Takeshi Seki et al.
A schematic showing the conversion of charge current to spin current based on the spin Hall effect in Co3Sn2S2. Image: Takeshi Seki et al.

A group of researchers has made a significant breakthrough that could revolutionize next-generation electronics by giving rise to spintronic devices with non-volatility, large-scale integration, low power consumption, high speed and high reliability. The researchers report their work in a paper in Physical Review B.

Spintronic devices utilize the magnetization direction of ferromagnetic materials for information storage and rely on spin current, a flow of spin angular momentum, for reading and writing data. But conventional semiconductor electronics have faced limitations in realising these properties.

However, the emergence of three-terminal spintronic devices, which employ separate current paths for writing and reading information, presents a solution that can deliver reduced writing errors and increased writing speed. Nevertheless, the challenge of reducing energy consumption during information writing, specifically via magnetization switching, remains a critical concern.

A promising method for mitigating energy consumption during information writing involves utilizing the spin Hall effect, where spin angular momentum (spin current) flows transversely to the electric current. The challenge lies in identifying materials that exhibit a significant spin Hall effect, a task that has been made difficult by a lack of clear guidelines.

"We turned our attention to a unique compound known as cobalt-tin-sulfur (Co3Sn2S2), which exhibits ferromagnetic properties at low temperatures below 177K (-96°C) and paramagnetic behavior at room temperature," explains Yong-Chang Lau and Takeshi Seki, both from the Institute for Materials Research (IMR) at Tohoku University in Japan and co-authors of the paper. "Notably, Co3Sn2S2 is classified as a topological material and exhibits a remarkable anomalous Hall effect when it transitions to a ferromagnetic state due to its distinctive electronic structure."

Lau, Seki and their colleagues employed theoretical calculations to explore the electronic states of both ferromagnetic and paramagnetic Co3Sn2S2, revealing that electron-doping enhances the spin Hall effect. To validate this theoretical prediction, the researchers synthesized thin films of Co3Sn2S2 partially substituted with nickel (Ni) and indium (In). These experiments demonstrated that while Co3Sn2S2 exhibited the most significant anomalous Hall effect, (Co2Ni)Sn2S2 displayed the most substantial spin Hall effect, aligning closely with the theoretical predictions.

"We uncovered the intricate correlation between the Hall effects, providing a clear path to discovering new spin Hall materials by leveraging existing literature as a guide," says Seki. "This will hopefully accelerate the development of ultralow-power-consumption spintronic devices, marking a pivotal step toward the future of electronics."

This story is adapted from material from Tohoku University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.