#magnons

A team of researchers affiliated with several institutions in Germany and Poland has demonstrated driven space-time crystals at room temperature. In their paper published in the journal Physical Review Letters, the group describes applying theories surrounding space-time crystals to magnons and how doing so allowed them to exploit electron spin in a way that could prove useful in information technology applications.

Crystals are defined by repeating pattern structures. Other research (by Frank Wilczek in 2012) has suggested that space-time crystals are defined in similar ways with structures that repeat in both time and space. More recent work has led to describing roadmaps for their creation in a lab setting. In this new effort, the researchers have used magnons (quasiparticles that are collective excitations of the spin structure of electrons in a crystal) to realize driven space-time crystals in a room temperature environment. The hope is that such structures, with their new state of matter, can be used to store information with far more energy efficiency than technologies in use now.

To create their space-time crystals, the researchers placed a length of nickel-iron alloy in a radio frequency field. Doing so resulted in the creation of excited magnons, which pushed them to assume a dynamic pattern—the researchers described them as similar to balls on a pool table, though in this case, all the balls returned to their initial positions after passing out of the radio frequency field.

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets. These materials make it possible to achieve computing speeds much faster than existing devices. Conventional devices using current technologies have the unwelcome side effect of getting hot and being limited in speed. This is slowing down the progress of information technology.

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The emerging field of magnon spintronics aims to use insulating magnets capable of carrying magnetic waves, known as magnons, to help solve these problems. Magnon waves are able to carry information without the disadvantage of the production of excess heat. Physicists at Johannes Gutenberg University Mainz (JGU) in Germany, in cooperation with theorists from Utrecht University in the Netherlands and the Center for Quantum Spintronics (QuSpin) at the Norwegian University of Science and Technology (NTNU) in Norway, demonstrated that antiferromagnetic iron oxide, which is the main component of rust, is a cheap and promising material to transport information with low excess heating at increased speeds. Their study has been published recently in the scientific journal Nature.