Influence of the oxygen content on the superconducting properties of bulk samples of YBa2Cu3O7−δ with 0.1 < δ < 0.35

Abstract

The oxygen doping parameter, δ, of YBa₂Cu₃O_7−δ bulk samples were determined using the double iodometric titration technique. The bulk samples exhibit orthorombic structure for the range of 0.1 < δ < 0.35, as expected. The charge carrier concentration n decreases with increasing δ. The transition temperature T_c exhibited a one-plateau function at the range of 0.1 < δ < 0.35. The slight expansion of the c-lattice parameter was attributed to the increase in oxygen content. A strong linear dependence with orthorombicity with δ was observed. The change in n, c-lattice parameter and orthorombicity, accompanied by changes in T_c with the oxygen content of the material were in accordance with the charge transfer model.