Chemical Oxidation on The Surface of La2CuO4 Single Crystals

Surface of La2CuO4 single crystals were oxidized by KMnO4 aqueous solutions. The oxidation conditions such as KMnO4 concentration, soaking time and solution temperature of KMnO4, were systematically controlled. The magnetic properties of the crystals were drastically dependent on the oxidation conditions. The superconducting transition properties under the optimum condition, 48 h, 150°C and 5 wt%, were T c = 28 K and ∆T c = 2K. The chemical oxidation was limited only to the surface region of the crystals. Therefore, chemical oxidation may be useful for the preparation of superconducting single-crystalline films.