Superconductivity in Be substituted by Ca in Cu0.5Tl0.5Ba2Ca n-1-yBe yCu nO2n+4-δ (n = 3, 4 and y = 0.7, 1.5, 1.7, 2.0)

The potential of Cu0.5Tl0.5Ba2Ca n-1-yBe yCu nO2n+4-δ superconductor have been realized by the substitution of Be at Ca site in our normal pressure synthesized Cu0.5Tl0.5Ba2Ca n-1Cu nO2n+4-δ (n = 3, 4) superconductors. The primary goal of synthesizing Be substituted samples was to achieve improve inter-plane couplings. Predominant single phases of Cu0.5Tl0.5Ba2Ca2-yBe yCu3O2n+4-δ (y = 0.7, 1.7) and Cu0.5Tl0.5Ba2Ca3-yBe yCu4O12-δ (y = 1.5, 2.0) superconductors were synthesized by the solid-state reaction method. The samples have shown a zero resistivity critical temperature around 95 K. The bulk superconductivity was measured by ac-susceptibility. The crystal structure of the material was determined by X-ray diffraction. The cell parameters have shown a decrease in the c-axis length with Be substitution. The decreased c-axis length suggests the improved inter-plane coupling in these superconductors. The increased inter-plane coupling is also evidenced by the softening of FTIR absorption modes of apical oxygen around 500 cm-1 and the CuO2 planner mode at 575 cm-1