Anisotropy in doped single crystal Bi2Sr2CaCu2O8+δ

Abstract Anisotropic transport properties have been investigated for single crystals Bi 2 Sr 2 CaCu 2 O 8+δ doped with Fe, Co, and Ni. The in-plane anisotropy ρ b (T)/ρ a (T) is temperature independent for all crystals. Out-of-plane resistivity ρ c increases in the case of doping with Co and Ni, while monotonously decreasing with increasing Fe concentration. The data of ρ c are well fitted by the activation-type phenomenological formula ρ c (T)=(a/T)exp(δ/T)+bT+c.