The superconducting and structural properties of S/F/S (Superconductor/Ferromagnet/Superconductor) heterostructures have been studied by means of microwave measurements (1-20 GHz) and x-ray absorption fine structure (XAFS) spectroscopy. Nb/PdNi/Nb trilayers have been studied as a function of F layer thicness. With respect to pure Nb, XAFS analysis shows that the heterostructures exhibit larger structural disorder in the S layers. Microwave measurements show evidence for a progressively weaker vortex pinning with increasing F thickness. However, no clear correlation is found with the local disorder in Nb: the weakest pinning is not in the most disordered trilayer. Therefore the structural disorder in the superconducting material cannot explain on its own the changes in vortex pinning. We argue that the F layer acts on the superconducting state itself. We propose possible explanations for the observed behavior.
@article{arxiv.1211.0173,
title = {Superconducting and structural properties of Nb/PdNi/Nb trilayers},
author = {N. Pompeo and K. Torokhtii and C. Meneghini and S. Mobilio and R. Loria and C. Cirillo and E. A. Ilyina and C. Attanasio and S. Sarti and E. Silva},
journal= {arXiv preprint arXiv:1211.0173},
year = {2012}
}