The effect of oxygen and hydrogen on superconductivity and ferromagnetism in Eu1.5Ce0.5RuSr2Cu2O10

Eu1.5Ce0.5RuSr2Cu2O10 is the first Cu-O based material in which superconduc tivity (SC) and ferromagnetism (FM) have been shown to coexist (T-C = 32 K, T-M = 122 K thus T-M > T-C). SC is confined to the CuO2 planes, and the ma gnetic ordering is due to the Ru sublattice. Hole doping in the CuO2 planes can be achieved with variation of oxygen or hydrogen concentrations. The e ffect of O is to increase T-C (up to 49 K) and T-M (up to 168 K). The effec t of H is to suppress SC and enhance the FM properties(T-M increases to 225 K). In contrast to other HTSC materials, this effect is reversible: by dep letion of hydrogen, SC is restored and T-M drops back to 122 K;. (C) 2000 E lsevier Science B.V. All rights reserved.