Uranium ruthenium silicide

Uranium ruthenium silicide (URu₂Si₂) is a heavy fermion alloy composed of uranium, ruthenium, and silicon. URu₂Si₂ has the same '122'-crystal structure as many other compounds of present condensed matter research. URu₂Si₂ is a superconductor with a "hidden order" (HO) phase below a temperature of 17.5 K. Below this temperature, it is magnetic, and below about 1 K it superconducts. However, the nature of the ordered phase below 17.5K is still under debate despite a wide variety of scenarios that have been proposed to explain this phase.