The pinning properties of type-II superconductors can be efficiently controlled by using laterally nanostructured ferromagnet / superconductor bilayers. This will be illustrated by studying the flux pinning in thin superconducting Pb films which are deposited on top of two types of magnetic nanostructures with out-of-plane magnetisation: (i) an array of dots, and (ii) an array of antidots, both made from a Co/Pt multilayer. The magnetisation curves of the Pb film are extremely asymmetric with respect to the polarity of the magnetic field when the magnetic moments in the Co/Pt multilayer were aligned prior to measurement. This asymmetry proves that magnetic contributions dominate the pinning potential that the magnetic nanostructures induce in the superconductor.
@article{arxiv.cond-mat/0201302,
title = {Nanostructured superconductor/ferromagnet bilayers},
author = {M. Lange and M. J. Van Bael and L. Van Look and S. Raedts and V. V. Moshchalkov and Y. Bruynseraede},
journal= {arXiv preprint arXiv:cond-mat/0201302},
year = {2007}
}
Comments
9 pages, 7 figures, to appear in the proceedings of the NATO Advanced Research Workshop on "New trends in superconductivity", Yalta (Ukraine), September 16 - 20, 2001)