Effects of Substitutions of Copper at the Chain Site on the Transport and Magnetic Properties of YBa[sub 2]Cu[sub 2](Cu[sub 1-x]M[sub x])O[sub 6+w].

We prepared polycrystalline samples of YBa[sub 2]Cu[sub 2](CU[sub 1-x]M[sub x])O[sub 6+w], where M (= Sc, Cr, V, Fe, Al and Au) substitutes copper in the chain site, and measured their transport and magnetic properties. The substitution level χ was 0.05 and 0.10 for each substituent. We determined the solubility of the different metals and the dependence of T[sub c], irreversibility lines and critical current density j[sub c] on M and χ. An improvement of j[sub c] by a factor larger than 2 was obtained in the Fe-, Al-, Cr- and Vsubstituted materials. No improvement of the irreversibility line was obtained for any substituent. [ABSTRACT FROM AUTHOR]