Strunk, Christoph and Paschen, U. and Surgers, C. and Löhneysen, H. v.
Pair-breaking mechanisms in Nb/Gd/Nb films.
Physica B Condensed Matter 194, pp. 2403-2404.
Several series of Nb/Gd/Nb triple layers have been grown in UHV by e--beam evaporation onto sapphire (1120BAR) substrates at 300 K. The superconducting transitions have been measured resistively and by dc-susceptibility, the ferromagnetic transition with the transverse magnetooptical Kerr effect. The Gd layers show long-range ferromagnetic order only above a layer thickness of 20 angstrom, which is attributed to the formation of a discontinuous film below this thickness. The superconducting properties of the films reflect this transition.by a sudden decrease in the T(c)(d(Gd))-curve with increasing d(Gd). This result indicates that pair breaking by the bulk-Gd exchange field is much more effective than pair breaking by spin-flip scattering. Depending on the thickness of the Nb layers T(c)(d(Gd)) saturates for large values of at a finite temperature or tends to zero.