Thermal relaxation in superconducting YBa sub 2 Cu sub 3 0 sub 7.
26 October 1987
A search for long-lived glassy states in sintered YBa sub 2 Cu sub 3 0 sub 7 has yielded negative results. The tunneling systems previously observed in acoustic measurements on the same samples therefore have a distribution of relaxation times that is cut off at long times (>100s). An unusual feature in the medium-time specific heat has been observed, a broad peak at T ~ 0.5K which resembles similar features in other high-T sub c superconductors.