We have investigated the mixed-state Hall resistivity ρxy and longitudinal resistivity σxx in HgBa2CaCu2O6, HgBa2Ca2Cu3O8, and Tl2Ba2CaCu2O8 thin films for various parameters, such as densities of columnar defects, number of CuO2 planes, and anisotropy ratios, as a function of the magnetic field up to 18 T. The scaling exponent β in ρxy = Aρxxβ is 1.9 ± 0.1 in the clean limit (CL) at high fields and low T whereas β is 1 β 0.1 in the moderately clean limit (MCL) at low fields and high T. We also find the triple sign reversal in the HgBa2CaCu2O6 films containing high-density columnar defects. These results can be interpreted within the context of a recent theory based on the midgap states in the vortex core.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering