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+d (TBCCO) thin films, in the ranges 58 K < T < Tc and 0 < l0H < 0.8 T. The large imaginary part Dq2(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 Dq1(H) and Dq2(H) can be collapsed on a pair of scaling curves Dq1[H/H*(T)], Dq 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