Interlayer magnetoresistance in the organic superconductor κ−(BEDT−TTF)₂Cu[N(CN)₂]Br near the superconducting

In this paper, we report transport measurements of interlayer magnetoresistance with field parallel and perpendicular to the current direction in the organic superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br. For H⊥J, the isothermal magnetoresistance R(H) displays a peak effect as a function of field. While the magnetoresistance at small field can be fitted to stacked Josephson junction model, the negative magnetoresistance is not consistent with quasiparticle tunneling model with a simple mean field gap. The origin for the peak effect remains unresolved. For H⊥J, R(H) increases monotonically with increasing field. Large magnetoresistance for H⊥J is consistent with the layered structure of the organic compounds.