Unconventional vortex dynamics in the low-field superconducting phases of UPt3

The flux dynamics at low magnetic fields in UPt3 shows a clear distinction between the relaxation of bulk vortices and those close to the surface. In addition, in the high-temperature A-phase, vortices trapped in the bulk of the specimen after cycling it in a magnetic field creep out as expected, while bulk vortices in the B-phase remain strongly pinned, indicating that an intrinsic, novel pinning mechanism exists in the low-temperature superconducting phase of UPt3

Unconventional flux dynamics in the heavy fermion superconductors UPt3 and UBe13

We have investigated flux creep in single crystals of UPt3 (Hc) and UBe13 (Hc4) in the temperature 5 mK < T < Tc and for magnetic fields H < 0. The relaxation curves for both of these heavy fermion superconductors show novel behaviours, with decay lows which depend strongly on the applied field. At all temperatures, we observe contributions to the decays which seem to arise from different processes with different time dependences, namely logarithmic and stretched exponential. © 1994

Unconventional flux dynamics in the heavy fermion superconductors UPt3 and UBe13

We have investigated flux creep in single crystals of UPt3 (Hc) and UBe13 (Hc4) in the temperature 5 mK < T < Tc and for magnetic fields H < 0. The relaxation curves for both of these heavy fermion superconductors show novel behaviours, with decay lows which depend strongly on the applied field. At all temperatures, we observe contributions to the decays which seem to arise from different processes with different time dependences, namely logarithmic and stretched exponential. © 1994

Unconventional vortex dynamics in the low-field superconducting phases of

The flux dynamics at low magnetic fields in $\rm UPt_3$ shows a clear distinction between the relaxation of bulk vortices and those close to the surface. In addition, in the high-temperature A-phase, vortices trapped in the bulk of the specimen after cycling it in a magnetic field creep out as expected, while bulk vortices in the B-phase remain strongly pinned, indicating that an intrinsic, novel pinning mechanism exists in the low-temperature superconducting phase of $\rm UPt_3$

Magnetic relaxation and quantum tunneling of vortices in polycristalline Hg0.8Tl0.2Ba2Ca2Cu3O8+sigma

Magnetic relaxation in a polycrystalline Hg0_8Tl0.2Ba2Ca2Cu30s+6 [(Hg,Tll-1223] superconductor was measured in the temperature range 1.85-20 K with different magnetic fields applied during the cooling process. The relaxation curves show a nearly perfect linear ln(t) behavior. The temperature dependence of the normalized relaxation rate, R = Id (M /M0)/dln(t)I, was studied for two applied magnetic fields. With the lower applied field (H.= 3 kOe), a temperature-independent R is found below 2.1 K and ex­plained in terms of quantum tunneling of vortices. As the applied field increases (H. = 10 kOe), the tran­sition from the thermal to the quantum regime is not found in the experimentally accessible temperature range above 1.85 K. The field dependence of R at 2.8 K is studied in order to analyze the dimensionality of the flux-line lattice