Electrical resistance and magnetic properties of double-doped ceramics La1.85−4∕3xSr0.15+4∕3xCu1−xMnxO4

Abstract

Resistive and magnetic measurements are made on La1.85−4∕3xSr0.15+4∕3xCu1−xMnxO4 ceramics with x=0.02, 0.04, 0.06, and 0.08. It is found that at these concentrations the temperature of the beginning and end of the superconducting transition depend weakly on the concentration x. The resistive properties exhibit a combination of metallic conductivity (or superconductivity) along the grains with hopping transport between grains. At low temperatures the superconductivity apparently coexists with two different magnetic phases.