Metal-insulator transition in Bi2Sr1.6−zLa0.4CuO6+δ induced by cation vacancies

Abstract The influence of Sr content on the superconducting properties of the series Bi 2 Sr 1.6−z La 0.4 CuO 6+δ (0 ≤ z ≤ 0.7) has been investigated by means of X-ray diffraction, electrical resistivity and magnetic susceptibility. The solid solution limit is z = 0.2. Higher z values show discontinuity in the variation of cell parameters and phase segregation. The physical properties change from superconducting, for low z values, to semiconducting for larger z. In the solid solution region, Tc is highly dependent on the Sr content, decreasing as z increases.