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The ability to switch magnetism, or, in other words, to change the orientation of a material's magnetic moments, using only electricity, could open new opportunities for the efficient storage of data in hard drives and other magnetic memory devices. While the electrical switching of magnetism has been a long-sought-after research goal, it has so far proved to be difficult to realize.

Researchers at Southern University of Science and Technology (SUSTech) in China and Peking University, led by Prof. Haizhou Lu and Prof. X. C. Xie, recently demonstrated the electrical switching of a particular form of magnetism known as altermagnetism, which was first discovered in 2022.

Their paper, in Â鶹ÒùÔºical Review Letters, could have important implications for the development of new technologies based on altermagnetic materials that can be controlled with electrical currents, without the need for external magnetic fields.

"Manipulating magnetism using only electricity is a long-standing challenge because of its great significance for industrial applications, such as high capacity and low-consumption storage," Yiyuan Chen, first author of the paper, told Â鶹ÒùÔº.

"The newly discovered altermagnetism, combining the advantages of both ferromagnetism and antiferromagnetism, such as easy read-out and high-frequency operation, may open a new avenue along this effort. Our paper is the first one addressing that altermagnetism can be switched by a pure electric current."

In 2022, researchers identified a new type of magnetism called altermagnetism, characterized by a zero net magnetization, symmetry-protected spin-splitting and unique symmetry patterns that impact the behavior of electrons. As switching other primary forms of magnetism using electrical currents proved challenging in the past, Chen and his colleagues set out to try and switch altermagnetism instead.

A key requirement for the switching of a material's magnetic configuration is the so-called breaking of parity symmetry (i.e., a system's invariance when spatial coordinates are inverted). They found that a material that naturally breaks parity symmetry is bilayer manganese telluride (MnTe), an altermagnetic compound consisting of Mn and Te atoms, specifically when it consists of five atoms arranged in a particular order (i.e., Te-Mn-Te-Mn-Te).

To demonstrate the electrical switching of altermagnetism in bilayer MnTe samples with this configuration, they used a combination of analysis methods, computational physics techniques and computer simulations. Their results were highly promising, suggesting that this material could in fact be a promising platform for the switching of magnetism without magnetic fields.

"We use symmetry analysis, first-principles calculations and magnetic dynamics simulations with the Landau-Lifshitz-Gilbert equation," explained Chen. "Our work pioneers the pure electric switching of altermagnetism, thus opening a new avenue for information storage devices. It will also inspire further explorations of unconventional magnetism and potential applications."

The recent work by Chen and his colleagues could soon pave the way for more studies aimed at demonstrating the electrical switching of altermagnetism in MnTe bilayer devices. In the future, it could contribute to the development of new electrically controlled data storage solutions or other electronics based on altermagnetic materials.

"We now aim to apply our theory to more unconventional magnetisms to achieve their deterministic switching," added Chen. "We are also looking for more readable signal of unconventional magnetism to further promote the application of unconventional magnetism in electronic devices."

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