MAGNETIC-BEHAVIOR OF A CR+1.6AT-PERCENT SI SINGLE-CRYSTAL

Measurements of thermal expansion and velocity of sound around the Neel temperature (T(N)) of a Cr + 1.6 at.% Si single crystal are presented. A weak continuous transition superimposed on a sharp first-order discontinuity was observed in the thermal expansion near T(N). The continuous component is accurately described by a critical exponent power law. The sound velocity diverges sharply near T(N) in contrast with theoretical predictions for Cr-like itinerant electron antiferromagnets.