{( La2-xSrxCuO4) m}/{( Ca1-zSrzCuO2) n} and {( Ba2CuO3+y) m}/{( Ca1-zSrzCuO2) n} superlattices prepared by laser ablation

The preparation of new materials with superlattice, consisting of La _{2- x}Sr _xCuO ₄ or Ba ₂CuO _{3+ y} and the infinite layer (Ca _{1- z}Sr _zCuO ₂) was studied to obtain CuO ₂ multilayered new copper-oxides. From the X-ray diffraction patterns and transmission electron microscopy (TEM) images on the {( La_2-xSr_xCuO₄) _m}/{( CaCuO₂) _n} superlattice, it was found that one, two or three unit cells of the infinite layer can be inserted between the La _{2- x}Sr _xCuO ₄ blocking layers. A slight bend was observed at around 105 K in the temperature-dependence curve of the resistivity ( ϱ- T curve) of the superlattice consisting of nine unit cells of La _1.6Sr _0.4CuO ₄ and two unit cells of CaCuO ₂. On the other hand, a bend was observed in the ϱ- T curve at about 150 K on the thin films being stacked up with ten unit cells of Ba ₂CuO _{3+ y} and three unit cells of CaCuO ₂ alternately.