title: In situobservation of magnetic orientation process of feeble magnetic materials under high magnetic fields.
abstract: Anin situmicroscopic observation of the magnetic orientation process of feeble magnetic fibers was carried out under high magnetic fields of up to 10 T using a scanning laser microscope. In the experiment, carbon fibers and needle-like titania fibers with a length of 1 to 20 μm were used. The fibers were observed to gradually orient their axes parallel to the direction of the magnetic field. The orientation behavior of the sample fibers was evaluated on the basis of the measured duration required for a certain angular variation. As predicted from the theoretical consideration, it was confirmed that the duration required for a certain angular variation normalized by the viscosity of the fluid is described as a function of the fiber length. The results obtained here appear useful for the consideration of the magnetic orientation of materials suspended in a static fluid.
authors.affiliation: International Center for Materials Nanoarchitectonics; Nano Ceramics Center, National Institute for Materials Science.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hirota
authors.affiliation: Department of Advanced Materials Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ando
authors.affiliation: Department of Advanced Materials Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of Advanced Materials Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Wada
authors.affiliation: International Center for Materials Nanoarchitectonics; Nano Ceramics Center, National Institute for Materials Science.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Sakka
keywords: in situ observation; magnetic anisotropy; magnetic orientation; magnetic torque; rotation time; viscous resistance