Conductivity anisotropy in Y1-yPryBa2Cu3O7-δ single crystals in a wide range of praseodymium concentrations

Abstract

Anisotropies of different conductivity mechanisms in Y 1-y Pr y Ba 2 Cu 3 O 7-δ single crystals in a wide range of praseodymium concentrations are reported, assuming a transition from the metallic conductivity to the semiconductor-like regime, in conjunction with the fluctuation conductivity within the 3D Aslamazov–Larkin model. The Tc anisotropy grows with increasing y, with a most drastic rise when approaching the non-superconducting composition. As the praseodymium concentration increases, the ideal resistance anisotropy passes through a maximum at y ≈ 0.19. The temperature dependence of the semiconductor-like resistance anisotropy exhibits a maximum associated with variable-range jumps along the c-axis. The temperature dependence of the fluctuation conductivity anisotropy passes through a maximum due to a significant anisotropy of the coherence length.