NOVEL MAGNETISM AND SUPERCONDUCTIVITY IN A Ru-BASED DOUBLE PEROVSKITE

Abstract

We report the observations, using magnetic susceptibility and specific heat measurements, of the coexistence of superconductivity and magnetic ordering at low temperatures in the Cu-doping double perovskites Sr 2 ARu 1-x Cu x O 6 , with A = Y or Ho, and x<0.2. The observed striking features can be understood in terms of a plausible theoretical model based on the double exchange mechanism, which occurs indirectly via Ru 5+ spin coupling to itinerant electrons hopping from one Ru site to another.