NEW MEMBERS OF SR-FREE BI-2201 CUPRATES - BI-2(LA,A)(2)CUOZ (A = NA AND K)

New members of Sr-free Bi-based cuprates with the 2201 structure have been synthesized in the Bi-2(La,A)2CuO(z) systems (A: Na and K). Almos t-single phase samples can be obtained at the nominal composition of B i(2)La(1.5)A(0.65)CuO(z), for both systems. The almost-single phase sa mples containing Na or K crystallize both in an orthorhombic lattice, and the lattice constants are a = 5.423 Angstrom, b = 5.473 Angstrom, c = 23.74 Angstrom for the sample containing Na and a = 5.445 Angstrom , b = 5.493 Angstrom, c = 23.85 Angstrom for the sample containing K. Both samples show a temperature dependence of In rho proportional to T -1/4 suggesting a three-dimensional variable range hopping conduction without any trace of superconductivity down to 5 K. (C) 1997 Elsevier Science B.V.