SYNTHESIS AND CHARACTERIZATION OF NEW CUPRATES WITH A (BI, IN)O MONOLAYER - (BI, IN)SR2(GD, CA)CU2OY

New cuprates of (Bi, In)Sr2Gd1-xCaxCu2Oy have been synthesized by the solid state reaction method in an oxidizing atmosphere. Powder X-ray diffraction (XRD) indicates that the samples have space group of P4/mmm with cell parameters of a=0.38378(5) nm, c= 1.1761(2) nm when x = 0. The compounds have the same crystal structure as Tl-1212 except for containing a (Bi, In)O monolayer rather than a TlO layer. Ca2+ substitution for Gd3+ (x less-than-or-equal-to 0.4) results in a decrease of the a-axis, which suggests that holes are induced in the CuO2 sheet. A semiconductor-to-superconductor transition occurs around x=0.3. The sample of x=0.4 exhibits superconductivity with a T(c)(onset)= 42 K and T(c)(zero) = 18 K from the measurement of the temperature dependence of resistivity.