title: Imaging of current density distributions with a Nb weak-link scanning nano-SQUID microscope.
abstract: Superconducting quantum interference devices (SQUIDs) are accepted as one of the highest magnetic field sensitive probes. There are increasing demands to image local magnetic fields to explore spin properties and current density distributions in a two-dimensional layer of semiconductors or superconductors. Nano-SQUIDs have recently attracting much interest for high spatial resolution measurements in nanometer-scale samples. Whereas weak-link Dayem Josephson junction nano-SQUIDs are suitable to miniaturization, hysteresis in current-voltage (I-V) characteristics that is often observed in Dayem Josephson junction is not desirable for a scanning microscope. Here we report on our development of a weak-link nano-SQUIDs scanning microscope with small hysteresis in I-V curve and on reconstructions of two-dimensional current density vector in two-dimensional electron gas from measured magnetic field.
authors.affiliation: Division of Physics, University of Tsukuba, Tennodai, Tsukuba, 305-8571, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shibata
authors.affiliation: Division of Physics, University of Tsukuba, Tennodai, Tsukuba, 305-8571, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Nomura
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kashiwaya
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kashiwaya
authors.affiliation: Department of Mathematical and Physical Sciences, Faculty of Science, Japan Women's University, Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan.|Department of Applied Physics, Faculty of Science, Tokyo University of Science, Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Ishiguro
authors.affiliation: Department of Applied Physics, Faculty of Science, Tokyo University of Science, Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takayanagi