Spin glass transition in disordered terbium.

While crystalline Tb is a helix antiferromagnet with a Neel temperature of 229K which becomes ferromagnetic at 222K, disordered Tb exhibits a spin-glass transition. The spin-glass freezing temperature ranges from 183 to 53K, the lowest temperatures corresponding to the greatest degree of atomic disorder. These experiments constitute the first evidence for an elemental spin-glass.