Vortex dissipation in Y_1−xPr_xBa₂Cu₃O_7−δ superconductors above and below the zero-field critical temperature

We investigated in-plane angular magnetoresistivity Δρ_ab∕ρ_ab(0°) below and above the zero-field critical temperature T_c0 of Y_1−xPr_xBa₂Cu₃O_7−δ single crystals with 0.0⩽x⩽0.53. The angular dependence of in-plane magnetoresistivity shows three temperature regimes: (a) a low T regime which extends from below to above the critical temperature T_c0, up to an x-dependent temperature (e.g., up to 1.15×T_c0 for x=0.46), displaying a two-dimensional (2D) scaling (consistent with pancakelike excitation), (b) an intermediate T regime, corresponding to vortex line excitations, which extends up to T_φ>T_c0, and (c) a high T regime in which the quasiparticles dominate the dissipation. The constructed electronic phase diagram shows that T_φ(x) departs from T_c0(x) for x⩾0.20 and reaches a maximum at x=0.46.