Electronic structure of Eu in high T sub c superconductor Ba sub 2 EuCu sub 3 0 sub (7.1).

The Mossbauer effect of the 22 keV gamma-line of sup (151) Eu has been employed to study the electronic configuration of Eu ions in the high T sub c superconducting material Ba sub 2 EuCu sub 3 O sub (7.1). The isomer shift is constant as a function of temperature and shows that Eu is present as Eu sup (3+) (4f sup 6).