Magnetic studies of strontium lanthanum copper oxides

We report measurements of static magnetic susceptibilities for a series of stronium-substituted lanthanum copper oxides prepared under identical conditions. These materials have recently been shown to exhibit bulk superconductivity with high critical temperatures. Measurements of the end member La2CuO4 provie evidence for a phase transition of unknown origin at 260 K. This phase transition is suppressed by the substitution of small amounts of strontium for lanthanum. Understanding the normal-state properties of SrxLa2-xCuO4- may provide important clues to the superconducting behavior of these materials.