Electronic properties of La-Cu oxides

Abstract Two anomalies are found in the temperature dependence of the d.c. electric conductivity of variously prepared La-Cu oxides: a shoulder around the temperature of T ⋍ 240 K, associated with a magnetic phase transition in La 2 CuO 4 and a decrease of resistance below 40 K associated with a yet to be identified superconducting La-Cu-O phase.