Contour map of Tc of (La1−xMx)2CuOy [M; Ba, Sr and Ca]

Abstract Using (La 1− x M x ) 2 CuO y [M; Ba, Sr and Ca] samples with well controlled composition, T c was determined as a function of x and y and contour maps constructed. The centers of superconduction subdomains were located at x =0.0 and x =0.05 to 0.08 on the line y =4.00. The contours were classified into kinds. The contours of one kind were parallel to the straight line of constant Cu valence. It was considered that T c was mainly determined by the concentration of holes. The contours of another kind were vertical. The vertical contours were interpreted in terms of the stability of lattice coupled with the concentration of holes.