Scaling of the microwave magneto-impedance in Tl2Ba2CaCu2O8+delta thin films

We present measurements of the magnetic field-induced microwave complex resistivity changes at 47 GHz in Tl2Ba2CaCU2O8+delta (TBCCO) thin films, in the ranges 58 K < T < T-c and 0 < mu H-0 < 0.8 T. The large imaginary part Delta rho(2)(H) points to strong elastic response, but the data are not easily reconciled with a rigid vortex model. We find that, over a wide range of temperatures, all the pairs of curves Delta rho(1)(H) and Delta rho(2)(H) can be collapsed on a pair of scaling curves Delta rho(1)[H/H*(T)], Delta rho(2)[H/H*(T)], with the same scaling field H*(T). We argue that H*(T) is related to the loss of vortex rigidity due to a vortex transformation. (c) 2007 Elsevier B.V. All rights reserved