Researchers at MIT have observed ferromagnetic behavior in a gas by cooling a gas of lithium atoms to 150 billionth of 1 Kelvin above absolute zero, or -273 degrees. The results suggest that a gas of elementary particles does not need a crystalline structure to be ferromagnetic. Wolfgang Ketterle, the John D. McArthur Professor of Physics, and David E. Pritchard, The Cecil and Ida Green Professor of Physics, lead the research team.
To accomplish these results, researchers trapped a cloud of ultracold lithium atoms in the focus of an infrared laser beam. After increasing the repulsive forces between the atoms, it became apparent that the gas had become ferromagnetic.
“The evidence is pretty strong,” says Pritchard, “but it is not yet a slam dunk. They started to form molecules and may not have had enough time to develop regions of aligned atoms large enough for us to see.”
The work was reported in the Sept. 18 issue of the journal Science.
[Source: R&D magazine]
