Scaling of the microwave magneto-impedance in Tl$_2$Ba$_2$CaCu$_2$O$_{8+\delta}$ thin films

TL;DR

This study investigates the microwave complex resistivity in Tl$_2$Ba$_2$CaCu$_2$O$_{8+eta}$ thin films under magnetic fields, revealing a universal scaling behavior linked to vortex rigidity loss.

Contribution

It demonstrates a universal scaling of microwave resistivity in TBCCO thin films and relates the scaling field to vortex transformation effects.

Findings

Resistivity exhibits a universal scaling with magnetic field.

Large imaginary resistivity indicates strong elastic vortex response.

Scaling field correlates with vortex rigidity loss.

Abstract

We present measurements of the magnetic field-induced microwave complex resistivity changes at 47 GHz in Tl$_2$Ba$_2$CaCu$_2$O$_{8+\delta}$ (TBCCO) thin films, in the ranges 58 K$<T<T_{c}$ and 0$<\mu_{0}H<$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.