title: A Tunable Magnetic Domain Wall Conduit Regulating Nanoparticle Diffusion.
abstract: We demonstrate a general and robust method to confine on a plane strongly diffusing nanoparticles in water by using size tunable magnetic channels. These virtual conduits are realized with pairs of movable Bloch walls located within an epitaxially grown ferrite garnet film. We show that once inside the magnetic conduit the particles experience an effective local parabolic potential in the transverse direction, while freely diffusing along the conduit. The stiffness of the magnetic potential is determined as a function of field amplitude that varies the width of the magnetic channel. Precise control of the degree of confinement is demonstrated by tuning the applied field. The magnetic conduit is then used to realize single files of nonpassing particles and to induce periodic condensation of an ensemble of particles into parallel stripes in a completely controllable and reversible manner.
authors.affiliation: Departament de Física de la Matèria Condensada, Universitat de Barcelona , Avenida Diagonal 647, 08028 Barcelona, Spain.|Institut de Nanociència i Nanotecnologia, Universitat de Barcelona , Barcelona, Spain.|Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona , Barcelona, Spain.
authors.forename: Pietro
authors.initials: P
authors.lastname: Tierno
authors.affiliation: Department of Physics, The University of Oslo , P.O. Box 1048 Blindern, 0316 Oslo, Norway.|Institute for Superconducting and Electronic Materials, University of Wollongong , Wollongong, New South Wales 2522, Australia.
authors.forename: Tom H
authors.initials: TH
authors.lastname: Johansen
authors.affiliation: Departament de Física de la Matèria Condensada, Universitat de Barcelona , Avenida Diagonal 647, 08028 Barcelona, Spain.|Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona , Barcelona, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Sancho
keywords: Diffusion; domain walls; magnetic thin films; nanofluidics