title: Direct observation of rectified motion of vortices in a niobium superconductor.
abstract: Using Lorentz microscopy to directly image vortices, we investigate vortex motion control and rectification in a niobium superconductor. We directly observe a net motion of vortices along microfabricated channels with a spatially asymmetric potential, even though the vortices were driven by an oscillatory field. By observing the individual motion of vortices, we clarify elementary processes involved in this rectification. To further demonstrate the ability to control the motion of vortices, we created a tiny vortex "racetrack" to monitor the motion of vortices in a closed circuit channel.
authors.affiliation: Frontier Research System, the Institute of Physical and Chemical Research (RIKEN), Hatoyama, Saitama 350-0395, Japan. ytogawa@harl.hitachi.co.jp
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Togawa
authors.forename: Ken
authors.initials: K
authors.lastname: Harada
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Akashi
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kasai
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Matsuda
authors.forename: Franco
authors.initials: F
authors.lastname: Nori
authors.forename: Atsutaka
authors.initials: A
authors.lastname: Maeda
authors.forename: Akira
authors.initials: A
authors.lastname: Tonomura