CONTOUR MAP OF T-C OF (LA1-XMX)(2)CUOY [M, BA, SR AND CA]

Using (La1-xMx)(2)CuOy [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 locat ed 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 w as mainly determined by the concentration of holes. The contours of an other kind were vertical. The vertical contours were interpreted in te rms of the stability of lattice coupled with the concentration of hole s. (C) 1998 Published by Elsevier Science Ltd.