A NEW FAMILY OF PB BASED 1222-CUPRATES (PB,MG)(SR,R)(2)(R',CE)(2)CU2OY (R,R' RARE-EARTH ELEMENT)

A series of new Pb based 1222 cuprates, (Pb,Mg)(Sr,R)(2)(R',Ce)(2)Cu2O y, has been reported in this paper. The structure of the compounds has been determined by the powder X-ray diffraction method. It crystalliz es in a tetragonal lattice with space group I4/mmm and lattice paramet ers a = 3.818 Angstrom and c = 29.085 Angstrom for R,R' = Nd,Dy. XRD r esults show that the structure is isostructural with (Pb,Cu)(Sr,R)(2)( R',Ce)(2)Cu2Oy with the (Pb,Mg)O layer replacing the (Pb,Cu)O layer. R esistivity measurements show that the compounds are semiconductors und er the present experimental conditions.