Antiferromagnetic spin switch: New approach for future electronics

In the realm of electronics, the traditional mode of operation relies on the movement of , with electrons shuttling from one point to another to generate current and transmit signals through the application of voltage. However, there exists an alternative avenue for manipulating electronic currents and signals—one that harnesses the intrinsic magnetic properties of electrons known as spin. This burgeoning field, aptly named “spintronics,” has emerged as a pivotal area of research in contemporary electronics.

In a significant breakthrough, an international research collaboration involving TU Wien and the Czech Academy of Sciences has achieved a remarkable feat: they have succeeded in manipulating the spins within an material using surface strain. This groundbreaking achievement holds the promise of opening up new avenues in electronic technologies and could pave the way for transformative advancements in the field. The findings of this research have been published in the prestigious journal Advanced Functional Materials.

Explaining the intricacies of magnetism, Sergii Khmelevskyi from the Vienna Scientific Cluster Research Center at TU Wien elucidates, “There exist various manifestations of magnetism, with ferromagnetism being the most familiar. In ferromagnetic materials, atomic spins align parallel to each other. Conversely, entails neighboring atoms possessing spins of opposite orientations, resulting in the cancellation of their magnetic effects, rendering the material non-magnetic when observed externally.”

Khmelevskyi highlights the seminal contribution made in 2010 by scientists from TU Wien and the Czech Academy of Sciences, who proposed that antiferromagnetic materials harbor promising attributes for spintronic . This seminal proposition laid the groundwork for the burgeoning field of “antiferromagnetic spintronics,” which has since witnessed rapid expansion and exploration.

The recent collaborative efforts of TU Wien, the Institute of Physics of the Czech Academy of Sciences, and Ecole Polytechnique (Paris) have been instrumental in advancing this frontier. Overcoming the inherent challenge posed by the intricate manipulation of spins within antiferromagnetic materials proved to be a formidable task. However, the successful development of a reliable and precise method for spin manipulation is paramount. Only through the targeted switching of magnetic states can the realization of essential components such as computer memory , including MRAM, be achieved.

Magnetic frustration: Tiny effects make all the difference

While manipulating ferromagnets is relatively straightforward—simply applying an external can alter their internal magnetic properties—the same cannot be said for antiferromagnets. However, a breakthrough solution lies in the manipulation of surface strain.

This method necessitates specific types of crystals, each with its unique geometry and atom arrangement. Depending on these factors, various antiferromagnetic spin configurations may emerge. The crystal tends to adopt the state with the lowest , but there are instances where multiple spin orders possess identical energy levels—an occurrence known as “magnetic frustration.”

“In such cases, seemingly insignificant interactions can dictate the magnetic state assumed by the crystal,” explains Khmelevskyi.

Experiments conducted with uranium dioxide have demonstrated that applying to compress the even slightly can induce a switch in the material's magnetic order.

“We have now demonstrated that antiferromagnets can indeed be manipulated by leveraging the of magnetic frustration present in numerous known materials,” Khmelevskyi states. “This discovery paves the way for exciting advancements in the realm of functional antiferromagnetic spintronics.”

Source: Vienna University of Technology

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