Resistive transition in π-junction superconductors

The resistivity behavior of inhomogeneous superconductors with random $\pi$ junctions, as in high-$T_c$ materials with d-wave symmetry, is studied by numerical simulation of a three-dimensional XY spin glass model. Above a concentration threshold of antiferromagnetic couplings, a resistive transition is found in the chiral-glass phase at finite temperatures and the critical exponents are determined from dynamic scaling analysis. The power-law exponent for the nonlinear contribution found in recent resistivity measurements is determined by the dynamic critical exponent of this transition.