Scaling behaviour and hall conductivity of mixed-state hall effect in heavy-ion irradiated YBa2Cu3O7 crystals

The Hall effect (ρxy) and longitudinal resistivity (ρxx) measured in YBa2Cu3O7 crystals before and after the irradiation of Sn and Xe ions. We found a clear evidence that the strong pinning induced by the columnar defects not only modifies the scaling behavior between the Hall resistivity ρxy and longitudinal resistivity ρxx but also affects the temperature dependence of the Hall conductivity. For the irradiated crystals with columnar defects, the scaling exponent β of ρxy = Aρxxβ was found to be β = 1.55 ± 0.1, whereas β of the unirradiated one was larger than 1.8. In case of the Hall conductivity, the pinning strength dependence was also observed. The Hall conductivity after irradiation exhibited a clear deviation from that of the unirradiated crystal at low temperatures. These results are in a good agreement with the work by Wang et al. in which pinning plays an important role