POSSIBLE ORIGIN FOR OSCILLATORY SUPERCONDUCTING TRANSITION-TEMPERATURE IN SUPERCONDUCTOR FERROMAGNET MULTILAYERS/

We have studied superconducting and magnetic properties of sputtered F e/Nb/Fe trilayers. For a fixed Nb thickness and with changing Fe thick ness, d(Fe), a nonmonotonic behavior of the superconducting transition temperature T-c was observed with a maximum at d(Fe) approximate to 1 0 Angstrom. The analysis of the magnetization data revealed that for d (Fe) less than or equal to 7 Angstrom the Fe layer is nonmagnetic. The interpretation of the observed T-c behavior is attributed to the exis tence of this magnetically ''dead'' layer and the change of the intera ction of the Cooper pairs with this layer at the onset of ferromagneti sm ford(Fe) greater than or equal to 7 Angstrom.