SUPERCONDUCTIVITY IN THE YBA2-YMYCU3OX (M=LA, PR) MATERIAL

We have investigated the substitution effects of La-and Pr-ions into t he Ba-sites on the superconductivity of YBa(2-y)MyCu(3)Ox (M=La, Pr). With increasing y value, orthorhombic to tetragonal phase transformati on occurs at y=0.35-0.4 and the resistivity behavior changes from meta llic to semiconductor-like at about y=0.4 for both substitution cases. The roles of non-magnetic element, La, and magnetic element, Pr, in t he superconductivity of YBa(2-y)MyCu(3)O(x) are nearly the same as a w hole besides the superconductivity is broken at y=0.6 for La-substitut ion and at y=0.7 for Pr-substitution. The magnetic property of the ele ments substituted into the Ba-site does not seem to be a critical para meter which determines the superconductivity of YBa2-yMyCu3Ox.