Soft chemical preparation and electrochemical oxygen doping of La2Can−1CunO2n+2

Abstract

La2CaCu2O6 (n = 2) was obtained at temperatures as low as 800 °C by firing the coprecipitates from a mixed aqueous solution of La, Ca, and Cu acetates which were titrated with tartaric acid. The firing temperature was much lower than that in solid state reactions which are usually conducted above 1000 °C. Both La2Ca2Cu3O8 (n = 3) and La2Ca3Cu4O10 (n = 4) were obtained at 700 °C in a similar preparation method. Low temperature firing was very important for these preparations. A porous sintered body of La2CaCu2O6 with a relative density of about 15% was also obtained using this preparation method. This porous sintered body could be effectively oxygen-doped by electrochemical oxidation showing the presence of a new superconducting phase with Tc around 30 K.