AVS 45th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Tuesday Sessions
       Session MI-TuA

Invited Paper MI-TuA5
Flux Pinning in Superconductors by Arrays of Submicron Structures*

Tuesday, November 3, 1998, 3:20 pm, Room 324/325

Session: Emerging Materials and Hybrid Structures
Presenter: I.K. Schuller, University of California, San Diego
Correspondent: Click to Email
We have used electron beam lithography to prepare triangular and square lattices, lines, etc. of submicrometer magnetic dots (Ni, Co, and Fe) and holes and studied their properties using a variety of techniques including magnetotransport, magnetization, Magnetic Force Microscopy and light scattering. We showed that the interaction between an ordered array of small magnetic particles and superconducting thin films leads to strong pinning effects due to the synchronized interaction with the vortex lattice. The resistivity vs. magnetic field curves present sharp minima close to the transition temperature, whereas the transport critical currents exhibit pronounced maxima. These minima and maxima appear at constant field intervals (@Delta@H), clearly related with the lattice parameter of the vortex lattice array. The angular dependence reveals that this interval @Delta@H increases with the angle between the field and the film normal (@theta@) as @Delta@H proportional to 1/cos@theta@, showing that only the perpendicular component of the magnetic field is relevant for this synchronized pinning effect. Comparisons with arrays of holes and normal submicrometric dots reveal the magnetic origin of these effects. Studies as a function of the various geometric parameters helps elucidating the pinning mechanisms involved. *Work done in collaboration with A. Hoffmann, Y. Jaccard, P. Prieto, M.-C. Cyrille, F. Sharifi, J. Martin, M. Velez, J. Nogues, J.-M. George, M. Grimsditch, M.J. Van Bael, K. Temst, C. Van Haesendonck, V.V. Moshchalkov and Y. Bruynseraede. Supported by the US-DOE and AFOSR.