Theory of Sm1.5Ce0.5Sr2Cu2NbO10: Critical-temperature and doping effects

For Sm1.5Ce0.5Sr2Cu2NbO10, the charge-reservoir oxygen model of superconductivity predicts: (i) Tc∼30 K (vs. the observed ∼28K); (ii) Roughly 1 percent Ni on Cu sites should drive Tc to zero; (iii) The superconductivity originates in the SrO layers; and (iv) The conduction, as with all high-temperature oxide superconductors, is necessarily p-type. The model also explains why this material can superconduct in the presence of the magnetic rare-earth ion Sm and why Gd on Sm sites does not destroy superconductivity, despite structural similarities to Sm2-zCezCuO4 and Gd2-zCezCuO4, although the former superconducts and-the latter does not