Transport properties of Tl2Ba2CaCu2O8 microbridges on a low-angle step substrate

Abstract

Tl-based superconducting devices have been drawn much attention for their high transition temperature (T c), which allow the high temperature superconductors (HTS) devices to operate at temperature near 100 K. The realization of Tl-based devices will promote the research and application of HTS devices. In this work, we present transport properties of Tl2Ba2CaCu2O8 (Tl-2212) microbridges across a low-angle step on LaAlO3 (LAO) substrate. We experimentally demonstrate intrinsic Josephson effects (IJEs) in Tl-2212 films by tailoring the geometry, i.e., reducing the width of the microbridges. In the case of a 1 μm width microbridge, in addition to the observation of voltage branches and remarkable hysteresis on the current–voltage (I–V) characteristics, the temperature dependence of differential resistance shows a finite resistance above 60 K when the bias current is below the critical current. For comparison, the wider microbridges are also investigated, exhibiting a highly critical current but do not showing obvious IJEs.