Rapid change of electronic anisotropy in overdoped (Y, Ca)Ba2Cu3O7−δ

Electronic anisotropy was studied for overdoped (Y, Ca)Ba2Cu3O7−δ with various doping levels (p). It was found that the pseudogap-like behavior in the resistivity disappear when p exceeds 0.17, independent of the oxygen deficiency. The anisotropy ratio γ estimated from upper critical fields showed a rapid decrease at around p = 0.18, approaching γ = 3 for p > 0.20.