A structural light switch for magnetism

June 23, 2020

Magnetic materials have been a mainstay in computing technology due to their ability to permanently store information in their magnetic state. Current technologies are based on ferromagnets, whose states can be flipped readily by magnetic fields. Faster, denser, and more robust next-generation devices would be made possible by using a different class of materials, known as antiferromagnets. Their magnetic state, however, is notoriously difficult to control.

Colorful arrows surround a central yellow peak in a dark background. — Depiction of the antiferromagnet CoF₂ transforming into a ferrimagnet under optical excitation. The red and blue arrows denote the original anti-parallel spins. Terahertz light pulses induce changes in the crystal structure that polarize the spins, creating a new magnetic state which can be used for information storage and processing.

© Jörg Harms / MPSD

Depiction of the antiferromagnet CoF₂ transforming into a ferrimagnet under optical excitation. The red and blue arrows denote the original anti-parallel spins. Terahertz light pulses induce changes in the crystal structure that polarize the spins, creating a new magnetic state which can be used for information storage and processing.

© Jörg Harms / MPSD

Now, a research team from the MPSD and the University of Oxford has managed to drive a prototypical antiferromagnet into a new magnetic state using terahertz frequency light. Their groundbreaking method produced an effect orders of magnitude larger than previously achieved, and on ultrafast time scales. The team’s work has just been published in Nature Physics.

More information you can find here.