In the mystifying world of quantum physics, a new finding has brought an intriguing twist to our understanding of magnetism. Scientists have discovered ‘stacked pancakes of liquid magnetism’ within layered helical magnets, offering a novel insight into their unique electronic behaviour.
Physicists at Rice University and Ames Laboratory have discovered ‘stacked pancakes of liquid magnetism’ in layered helical magnets. The materials exhibit unusual electronic behaviour – they are magnetic at cold temperatures and become nonmagnetic as they warm. The research, which involved creating a computational model to simulate the quantum states of atoms and electrons in these materials, has revealed fascinating insights into the magnetic phase transitions.
Unraveling the Magnetic Mystery
Helical magnets have been a subject of interest for physicists, especially due to their perplexing electronic behaviour. The materials demonstrate magnetism when cold and lose this property as they warm up. Makariy Tanatar, an experimental physicist at Ames National Laboratory, observed this intriguing behaviour in layered helimagnetic crystals.
The Computational Model and Quantum Interactions
Tanatar, along with Rice theoretical physicist Andriy Nevidomskyy and former Rice graduate student Matthew Butcher, devised a computational model to simulate the quantum states of atoms and electrons within these layered materials. By running thousands of Monte Carlo computer simulations, the team examined how the magnetic dipoles of atoms inside the material arranged themselves during the warming process.
From Solid Magnetism to Liquid Magnetism
As these helimagnets warm up, they undergo a phase transition, similar to a “thawing” process, turning from magnetic to nonmagnetic. The team’s model revealed an intermediate phase during this transition, where dipole interactions within each layer were stronger than those between the layers. The dipoles exhibited correlations more reminiscent of a liquid than a solid. This led to the intriguing ‘pancake’ structure of these liquid-like magnetic layers.
Anisotropy and Quantum Materials
Another surprising aspect was the directional behaviour, or anisotropy, of the materials. As Nevidomskyy explains, “These layered materials don’t look the same in the vertical and horizontal directions.” This anisotropy is a typical characteristic of many quantum materials, including high-temperature superconductors.
This discovery of liquid magnetism in helical magnets has opened up new research avenues, especially in the study of anisotropic materials like high-temperature superconductors. The study might provide clues about the yet-unexplained physics of these superconductors. The researchers also suggest the possibility of suppressing long-range magnetic ordering to give rise to effects brought about by strong quantum fluctuations, providing a novel direction for future studies.