Normal-state anomalies in the transport and magnetic properties in the (La1-xPrx)(1.85)Sr0.15CuO4 system and their correlation with T-c suppression: A signature of the effects of orthorhombic distortions

The correlation between the normal-state anomalies observed in the magnetic and transport properties of the (La1-xPrx)(1.85)SR0.15CUO4 system with 0 l ess than or equal to x less than or equal to 0.5 was studied. The x-ray-dif fraction patterns revealed a linear increase of the (a-b) orthorhombic para meter with the Pr content. The resistivity curves showed an increasing devi ation from linearity below similar to 100 K. This anomaly was properly acco unted by a logarithmic term, whose coefficient C linearly increases with x. Superconducting quantum interference device measurements of the normal-sta te magnetic susceptibility evidenced a deviation from the Pr3+ Curie-Weiss behavior in the same temperature range for which the resistivity anomaly oc curs. This behavior is explained in terms of an induced magnetic moment at the CuO2, layers under strain. A Dzialoshinsky-Moriya interaction, associat ed to the orthorhombic distortions, is proposed to be the source of a weak canted ferromagnetic component, which develops in conjunction with an enhan cement of the antiferromagnetic correlations. A comprehensive picture of th e conduction mechanism for the whole system is presented in terms of a Kond o-like scattering of the mobile holes by the spin fluctuations at the condu ction planes. T-c suppression was found to correlate with C, suggesting tha t the excitation which interacts with the carriers in the normal state is r elevant for superconductivity. [S0163-1829(99)11505-4].