Dependence of superconducting transition temperature on the hole concentration per CuO2 sheet in the oxide superconductor

Important information about the mechanism of superconductivity in the high T-c oxides can be extracted from the measurements of substitution effect on T-c. It is widely accepted that the oxygen atoms play a key role in these materials. For this reason a systematic study of the effect of substitution on structure and superconducting transition temperature in the light of oxygen content has been carried out on aliovalent doped series of samples of YBa2Cu3Oz (Y-123) superconductor. The variation of the transition temperature T-c with oxygen content in the Y1-xNaxBa2Cu3Ox superconductor is analysed in terms of P+, the hole concentration per CuO2 sheet This analysis shows that the nature of these variations are similar to those observed in other oxide families suggesting that p(+) is an important variable in governing the superconductivity in cuprate superconductors.