Specific Heat of (U0.97Th0.03)Be13 under Pressure

The specific heat, C, of (U0.97Th0.03)Be13 has been measured for 0.1≤T≤1K and 1.6≤P≤7.7 kbar, and for 0.1≤T≤20K with P=0. For T>8K both the pure and Th substituted samples have essentially the same C. The peaks in C/T at 0.33 and 0.54K for P=0 are suppressed and shifted to lower T by pressure. Anomalies in C/T can be correlated to corresponding rapid changes in magnetic susceptibility, χ Rapid suppression of the peaks and shift of Tc to lower values is in marked contrast to the behavior found for pure UBe13 whose single peak amplitude decreases approximately linearly with P to about 60% at 9.3 kbar. The broad “shoulder” in C/T near 2K that is found for UBe13, but not for any other heavy-fermion compound, HFC, is commpletely suppressed in the Th substituted sample. © 1987 The Japan Society of Applied Physics