Anomalous Hall effect and vortex pinning in high-Tc superconductors

Pulsed high-current-density measurements of the Hall effect in the mixed state in several high-Tc superconductors allow for a systematical tuning of the balance between Lorentz and pinning forces on the vortices. The characteristic temperatures for the single sign reversal in YBa2Cu3O7-? and those for the double sign change of the Hall effect in optimally-doped Bi2Sr2CaCu2Ox are independent of current density. This confirms that the observed sign changes of the vortex Hall effect are intrinsic properties and are not evoked by vortex pinning. In contrast, underdoped Bi2Sr2CaCu2Ox does not exhibit a sign reversal of the Hall effect but a negative contribution to the Hall conductivity can be detected when pinning is reduced in high-current densities. Π2001 Elsevier Science B.V. All rights reserved.