Anomalous Critical-Point Behavior in Europium Metal

Abstract
We have used Mössbauer‐effect measurements of the hyperfine (hf) interaction in Eu metal to study the behavior of its sublattice magnetization just below the Néel temperature. From about 0.9≤T/Tc≤0.99, the hf field is accurately proportional to (1−T/Tc)β with β=0.20, but at 0.99Tc, the hf field falls from 0.4 of saturation to zero. This can be explained by the existence of a first‐order transition coincident with the magnetic ordering.