A team of physicists from the New York University has discovered a new type of magnet that could change the way we store information. The idea for this type of magnet surfaced in the 1960s, and the basis of how it works was different from any other magnet known to scientists.
The magnet in question is called “singlet-based” magnet.
In conventional magnet, small magnetic constituents line up with one another to induce a strong magnetic field effect. However, in singlet-based magnet, the magnetic components emerge in and out of existence, generating an unstable force – but offers even better flexibility than conventional counterpart.
“There’s a great deal of research these days into the use of magnets and magnetism to improve data storage technologies,” explained Andrew Wray, lead author of the study, in a news release. “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.”
For a typical magnet, exposing to heat can basically disrupt the alignment of the “magnetic moments” and thus eliminate the magnetism. But the proposition of this pioneering idea of the 60s was that material with maladjusted alignment or no magnetic moments could still be magnet because there is such thing as a “spin exciton” – a kind of temporary magnetic moment which appears when electron interact with one another under the right condition.
“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 explained.
Then following a smorgasbord of scattering experiments and theoretical simulations, they established the link between the behaviors of a far more powerful magnet, called USb2 (a compound of uranium and antimony), and the theorized characteristics of singlet-based magnets. In other words, USb2 possesses all the fundamental ingredients for this type of “singlet-based” magnetism, and it exhibits a property called “Hundness.”
Hundness is a key quantum mechanical property that regulates how electrons generate magnetic moments. It has been shown to have paramount importance for a range of mechanical properties, including superconductivity.
“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,” said Lin Miao, a postdoctoral fellow involved in the study.
Reference: High temperature singlet-based magnetism from Hund’s rule correlations (Nature Communications)