Scaling of the microwave magneto-impedance in Tl2Ba2CaCu2O8 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†<†Tc and 0†<†[mu]0H†<†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.