Time Dependent Magnetization in the Heavy Fermion Superconductor UBe13

We have measrued the D.C. magnetization of the heavy fermion superconductor UBe13 in both the superconducting and normal state to high magnetic fields. We find an exponential time dependence for the relaxation of the mixed-state magnetization which supports the mechanism of flux jump. τ is both temperature and field dependent and UBe13 behaves differently from similar experiments in conventional type II superconductors in this respect. Other substantial difference between the two include observation of a paramagnetic background and evidence for anisotropy effects in the single crystal of UBe13 studied. These results will be discussed in light of recent theoretical and experimental work on heavy fermion systems. © 1987 The Japan Society of Applied Physics