Precise measurements of magnetic moment relaxation of YBa2Cu3O7-δ films were carried out in temperature range 4.2 K < T < 80 K at low magnetic field H ≈910 Oe. Temperature dependence of the glassy exponent μ of dependence of the activation energy U for vortices motion on current J was analyzed. It was obtained that μ increases from negative values at low temperatures T ≤ 10 K to μ ≈1-2 at T ≈40 K and decreases down to negative values at high temperatures T ≥70 K. It was shown that widely used Maley's technique and analysis of T/S(T) vs 1/J(T) dependence are unable to describe correctly strong μ(T) dependence observed in our experiments.
Sannikov, I. I., Ivanov, A. A., Kuznetsov, A. V., Menushenkov, A. P., & Churkin, O. A. (2015). Temperature Dependence of Glassy Exponent in YBa2Cu3O7-δ Films. In Physics Procedia (Vol. 65, pp. 113–116). Elsevier. https://doi.org/10.1016/j.phpro.2015.05.148