Na-doped YCa2Cu4O7-δ oxides are prepared by solid state diffusion of heating the reacting oxides (standard ceramic technique). The X-ray diffraction measurements show that the Na-doped YCa2Cu4O7-δ is single phase orthorhombic structure by annealing below 900°C under oxygen atmosphere. It is observed that, increase in Na content, the orthorhombic distortion decreases
