Frustrated magnets showing features of Hall Effect stun Princeton University researchers


Frustrated-Magnets



Excerpt from worldtechtoday.com

A group of researchers at the Princeton University has found that frustrated magnets, inspite of not possessing any magnetic feature at low temperatures, do exhibit features of Hall Effect. ‘Frustrated’ magnets are so called because of their inability of getting a long range magnetic order inspite of a huge exchange between the spins of their elementary particles.

The Hall Effect suggests that when magnetic field is applied to electric current carried by charged particles present in a conductor, it causes magnet to bend to the other side of semi-conductor. They are of great interest in physics and material science. Appreciating that frustrated magnets are capable of producing Hall Effect could hold the key to future advances in computing and the creation of devices such as quantum computers.

“To talk about the Hall Effect for neutral particles is an oxymoron, a crazy idea,” said N. Phuan Ong, one of the authors of the study and Eugene Higgins Professor of Physics at Princeton.

Inspite of that, he together with his colleague, Princeton’s Russell Wellman Moore Professor of Chemistry as well as their graduate students Max Hirschberger and Jason Krizan witnessed this unusual behavior in frustrated magnets.

“All of us were very surprised because we work and play in the classical, non-quantum world. Quantum behavior can seem very strange, and this is one example where something that shouldn’t happen is in reality there. It really exists,” said Ong in a statement.
The researchers wanted to find out the reason underlying “discontent” nature of Hall Effect.

In this particular case, the team led by Ong and Moore studied pyrochlores, a class of magnets ‘which should have orderly “spins” at very low temperature, but have been found to have spins that point in random directions, thus rendering them with magnetic frustration properties.’ They attached small electrodes to both sides of crystals and later passed heat through them using microheaters at extremely low temperatures.

The outcome of the experiment, states Ong, stunned the entire team.