Specifically, the team observed the ferromagnetic behavior in a gas of lithium atoms cooled to 150 billionth of 1 Kelvin above absolute zero (-273 degrees C or -459 degrees F). Team members used the lithium-6 isotope, which consists of three protons, three neutrons and three electrons. Since the number of constituents is odd, lithium-6 is a fermion — a class of exotic particles that have a half-integral spin — and has properties similar to an electron. Therefore, lithium atoms can be used to simulate the behavior of electrons.
|Why it matters|
|For decades, scientists have debated whether it is in principle possible for a gas or liquid of fermions, which are not in a periodic crystal, to become ferromagnetic.|
|The MIT research appears to provide a compelling affirmative answer to this question.|