PREDICTED PROPERTIES OF ND1.5CE0.5SR2CU2NBO10 AND RELATED HIGH-TEMPERATURE SUPERCONDUCTORS

The charge-reservoir oxygen model of superconductivity predicts a crit ical temperature of T-c approximate to 30 K for R1.5Ce0.5Sr2Cu2MO10 (R 222M-10) (with R=Eu, Sm, and Nd, and M=Ta and Nb), in agreement with t he measured values approximate to 28 K. The model also successfully pr edicts RBa2Cu2MO8 (R122M-8) to be an insulator. Other predictions for R222M-10 in need of testing are (i) it is a p-type superconductor; (ii ) the superconductivity originates primarily in the Sr-O layers, not i n the cuprate-planes; (iii) on cuprate-plane Cu sites, of order simila r to 1% Ni should depress T-c to zero, while about six times as much Z n will be required to destroy superconductivity; (iv) magnetic impurit ies on Cu sites and Sr sites, but not rare-earth sites, will break Coo per pairs; (v) Pr on Sr sites will suppress T-c; (vi) the failure of P r1.5Ce0.5Sr2Cu2MO10 to superconduct is due to the antistructure defect (PrSr+3SrPr+2); (vii) T-c is small because the primary superconductin g condensate in the charge-reservoir Sr-O layers is only approximate t o 2 Angstrom from the cuprate-planes; and (viii) the superconductivity should disappear with heavy Ce doping (z --> 1) in R2-zCezSr2Cu2MO10. The relationships of R222M-10 to R122M-8, RBaCu3O7, and R2-zCezCuO4 a re discussed. [S0163-1829(98)10517-9].