Controlled Manipulation of Individual Vortices in a Superconductor
  We report controlled local manipulation of single vortices by low temperature magnetic force microscope (MFM) in a thin film of superconducting Nb. We are able to position the vortices in arbitrary configurations and to measure the distribution of local depinning forces. This technique opens up new possibilities for the characterization and use of vortices in superconductors. 
E. W. J. Straver, J. E. Hoffman, O. M. Auslaender, D. Rugar, Kathryn   A. Moler