Low-temperature specific heat of the heavy electron superconductor U1-xThxBe13(x=0, 0.033) in external magnetic fields

We report on results of low-temperature specific-heat measurements of the u nconventional superconductors UBe13 and U0.9669Th0.0331Be13 in external mag netic fields up to 7 T. For T << T-c or, respectively, T-c2 for the thoriat ed sample, the magnetic field-induced contribution to C-p(T,B) varies linea rly with temperature, which is consistent with the temperature dependence o f the specific heat due to the flow of supercurrent around the vortices. (C ) 2000 Elsevier Science B.V. All rights reserved.