Paraconductivity and excess hall conductivity in (formula presented) superlattices

The paraconductivities and excess Hall conductivities of (Formula presented) films and (Formula presented) superlattices at temperatures above (Formula presented) are measured and analyzed within the framework of fluctuation theories. We observe that the fluctuation contributions to the paraconductivity of YBCO/PBCO superlattices are governed by the Lawrence and Doniach process and the dimensionality is characterized by the coupling parameter α, which is temperature dependent. However, the contributions of fluctuation to the excess Hall effect contain the negative Aslamazov-Larkin (AL) term and the positive Maki-Thompson (MT) term. Especially, the positive MT contributions for YBCO/PBCO superlattices suggest that the pair-breaking interaction is important when T is close (Formula presented) The scaling of the paraconductivities in the presence of magnetic fields suggests that the YBCO/PBCO superlattices belong to the quasi-two-dimensional (quasi-2D) systems and the anisotropic parameter (Formula presented) governs the dimensionality. With a smaller value of γ, a 2D-like scaling of the paraconductivities is obtained. On the other hand, in the scaling of the excess Hall conductivities, only the AL terms separated from the total conductivities follow a scaling law, while the MT terms do not. The results are discussed.