Density-of-states fluctuation-induced negative out-of-plane magnetoresistance in overdoped Bi-2212

Abstract

We analyzed the in-plane and out-of-plane magnetoresistance (MR) for overdoped Bi${}_{1.6}$Pb${}_{0.4}$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ (Bi-2212) single crystals using superconductive fluctuation theory, which considers the density-of-states (DOS) contribution in layered superconductors with the conventional s-wave pairing state. The out-of-plane results are well reproduced by the theory, implying that the large, negative out-of-plane MR as well as the sharp increase in the zero-field out-of-plane resistivity ${\rho }_c$ near the superconducting transition temperature $T_c$ originate from the superconductive DOS fluctuation effect. On the other hand, the in-plane results are better reproduced without the DOS contribution (i.e., using only the Aslamazov-Larkin (AL) contribution), which may be explained in terms of the d-wave superconductivity of the layered superconductors.

4 pages, 3 figures, 27th International Symposium on Superconductivity, ISS 2014, to appear in Physics Procedia