Investigation of the Transitions in UPd3.

Abstract Specific heat measurements below 20 K on UPd 3 in different magnetic fields up to 13 T are presented. With no field the sample shows a sharp transition at 6.37 K accompanied by two smaller maxima at 4.35 and 7.45 K. In the field these maxima shift upwards in temperature. In addition, the strain sensitivity of the anomalies has been investigated through specific heat measurements on a pressed pellet of finely ground powder. The main peak decreases in size upon grinding and its transition temperature goes down to 5.6 K. The results are interpreted to distinguish between the extant competing explanations of the main anomaly, as well as to shed light on the two smaller transitions.