A team of scientists has discovered the first robust example of a new type of magnet--one that holds promise for enhancing the performance of data storage technologies.
This "singlet-based" magnet differs from conventional magnets, in which small magnetic constituents align with one another to create a strong magnetic field.
In a normal magnetic material, dense magnetic moments try to align with their neighbors (left). By contrast, in a singlet-based material, unstable magnetic moments pop in and out of existence, and stick to one another in aligned clumps (right).
Credit: Lin Miao, NYU's Department of Physics
Usage Restrictions: In conjunction with this paper only.
By contrast, the newly uncovered singlet-based magnet has fields that pop in and out of existence, resulting in an unstable force--but also one that potentially has more flexibility than conventional counterparts.
"There's a great deal of research these days into the use of magnets and magnetism to improve data storage technologies," explains Andrew Wray, an assistant professor of physics at New York University, who led the research team.
"Singlet-based magnets should have a more sudden transition between magnetic and non-magnetic phases. You don't need to do as much to get the material to flip between non-magnetic and strongly magnetic states, which could be beneficial for power consumption and switching speed inside a computer.
"There's also a big difference in how this kind of magnetism couples with electric currents. Electrons coming into the material interact very strongly with the unstable magnetic moments, rather than simply passing through. Therefore, it's possible that these characteristics can help with performance bottlenecks and allow better control of magnetically stored information."
The work, published in the journal Nature Communications, also included researchers from Lawrence Berkeley National Laboratory, the National Institute of Standards and Technology, the University of Maryland, Rutgers University, the Brookhaven National Laboratory, Binghamton University, and the Lawrence Livermore National Laboratory.
The idea for this type of magnet dates back to the 1960s, based on a theory that stood in sharp contrast to what had long been known about conventional magnets.
A typical magnet contains a host of tiny "magnetic moments" that are locked into alignment with other magnetic moments, all acting in unison to create a magnetic field. Exposing this assembly to heat will eliminate the magnetism; these little moments will remain--but they'll be pointing in random directions, no longer aligned.
A pioneering thought 50 years ago, by contrast, posited that a material that lacks magnetic moments might still be able to be a magnet. This sounds impossible, the scientists note, but it works because of a kind of temporary magnetic moment called a "spin exciton," which can appear when electrons collide with one another under the right conditions.
"A single spin exciton tends to disappear in short order, but when you have a lot of them, the theory suggested that they can stabilize each other and catalyze the appearance of even more spin excitons, in a kind of cascade," Wray explains.
In the Nature Communications research, the scientists sought to uncover this phenomenon. Several candidates had been found dating back to the 1970s, but all were difficult to study, with magnetism only stable at extremely low temperatures.
Using neutron scattering, X-ray scattering, and theoretical simulations, the researchers established a link between the behaviors of a far more robust magnet, USb2, and the theorized characteristics of singlet-based magnets.
"This material had been quite an enigma for the last couple of decades--the ways that magnetism and electricity talk to one another inside it were known to be bizarre and only begin to make sense with this new classification," remarks Lin Miao, an NYU postdoctoral fellow and the paper's first author.
Specifically, they found that USb2 holds the critical ingredients for this type of magnetism--particularly a quantum mechanical property called "Hundness" that governs how electrons generate magnetic moments. Hundness has recently been shown to be a crucial factor for a range of quantum mechanical properties, including superconductivity.
This research, which also included NYU doctoral candidates Yishuai Xu, Erica Kotta, and Haowei He, was supported by the MRSEC Program of the National Science Foundation (DMR-1420073).
Alternate media contact: Ashley White, Lawrence Berkeley National Laboratory: firstname.lastname@example.org
James Devitt | EurekAlert!
Fusion by strong lasers
06.12.2019 | Helmholtz-Zentrum Dresden-Rossendorf
NASA's OSIRIS-REx mission explains Bennu's mysterious particle events
06.12.2019 | NASA/Goddard Space Flight Center
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...
Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.
Fibroblasts kit - ready to heal wounds
Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.
In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
06.12.2019 | Earth Sciences
06.12.2019 | Life Sciences
06.12.2019 | Information Technology