SUPERCONDUCTING AND MAGNETIC-PROPERTIES OF EPITAXIAL HIGH-QUALITY FE NB BILAYERS/

Single crystal Fe/Nb (110) bilayers with an Nb thickness d(Nb) in the range from 140 to 650 Angstrom and with an Fe thickness d(Fe) in the r ange from 5 to 100 Angstrom were prepared using molecular beam epitaxy (MBE) techniques. For d(Fe)greater than or equal to 20 Angstrom a dec rease of the superconducting transition temperature T-c with decreasin g d(Nb) was observed. For d(Fe)=20 Angstrom the FMR data revealed a de crease of the effective magnetization of the Fe layer below the superc onducting transition. This magnetization behavior is attributed to a s patial modulation of ferromagnetic order due to a modification of the RKKY interaction in the superconducting state. (C) 1997 American Insti tute of Physics.