HEAT-CAPACITY OF GADOLINIUM NEAR THE CURIE-TEMPERATURE

High-resolution ac calorimetric data near the Curie point are reported for several single crystals of gadolinium. The critical temperature and the shape of the heat-capacity curve near T(c) both depend on the sample-preparation procedure, including heat treatments. The heat-capacity data are analyzed in terms of predictions of renormalization-group theory. This analysis shows that the critical behavior of Gd is consistent with the picture of a complex critical behavior consisting of a series of crossovers dictated by the interplay between short-range and magnetic-dipolar interactions.