Since 1987, a third state of magnetism, one that could be highly relevant to high-temperature semiconductors, has been a theoretical prediction. Now researchers at MIT have demonstrated experimentally the existence of a fundamentally new kind of magnetic behavior (and a new form of matter), adding to the two previously known magnetic states (ferromagnetism and antiferromagnetism).
According to MIT:
“The experimental work showing the existence of this new state, called a quantum spin liquid. QSL is a solid crystal, but its magnetic state is described as liquid: Unlike the other two kinds of magnetism, the magnetic orientations of the individual particles within it fluctuate constantly, resembling the constant motion of molecules within a true liquid. There is no static order to the magnetic orientations, known as magnetic moments [i.e. the spin of the electrons], within the material. But there is a strong interaction between them, and due to quantum effects, the [magnetic orientations] don’t lock in place.”
To prove its existence, researchers had to first grow an artificial crystal known as herbertsmithite (named after mineralogist Herbert Smith , duh). The crystal growing process took an agonizing 10 months to complete. The researchers then used a neutron spectrometer and a technique called “neutron scattering” to scatter a beam of neutrons off of the crystal to determine if the electrons in the crystal could form a “spin liquid”, a state of matter in which the electrons magnetic orientation remains in a constant state of change. In MIT’s experiment, instead of all the scattered neutrons possessing identical energies at a given momentum, as they do with most magnetic materials, the neutrons had a wide spectrum of energies. This is hard evidence that Herbertsmithite indeed has spin-liquid properties of a QSL.
This new quantum spin liquid (QSL) state could lead to significant advances in data storage, new types of communications systems, and more.