title: Electric Conductivity and Dielectric-Breakdown Behavior for Polyurethane Magnetic Elastomers.
abstract: The electric-voltage dependence of the electric conductivity for cross-linked and un-cross-linked magnetic elastomers was measured at various magnetic fields, and the effect of cross-linking on the electric conductivity and the dielectric-breakdown behavior was investigated. The electric conductivity for un-cross-linked elastomers at low voltages was independent of magnetic fields and the volume fraction of magnetic particles, indicating the electric conduction in the polyurethane matrix. At high voltages, the electric conductivity increased with the magnetic field, showing the electric conduction via chains of magnetic particles. On the other hand, the electric conductivity at low voltages for cross-linked elastomers with volume fractions below 0.06 was independent of the magnetic field, suggesting the electric conduction in the polyurethane matrix. At volume fractions above 0.14, the electric conductivity increased with the magnetic field, suggesting the electric conduction via chains of magnetic particles. At high voltages, the electric conductivity for cross-linked elastomers with a volume fraction of 0.02 was independent of the magnetic field, indicating the electric conduction through the polyurethane matrix. At volume fractions above 0.06, the electric conductivity suddenly increased at a critical voltage, exhibiting the dielectric breakdown at the bound layer of magnetic particles and/or the discontinuous part between chains.
authors.affiliation: Graduate School of Science and Technology, Niigata University , Niigata 950-2181, Japan.|ALCA, Japan Science and Technology Agency , Tokyo 102-0076, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Sasaki
authors.affiliation: Graduate School of Science and Technology, Niigata University , Niigata 950-2181, Japan.|ALCA, Japan Science and Technology Agency , Tokyo 102-0076, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Tsujiei
authors.affiliation: Graduate School of Science and Technology, Niigata University , Niigata 950-2181, Japan.|ALCA, Japan Science and Technology Agency , Tokyo 102-0076, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Graduate School of Science and Technology, Niigata University , Niigata 950-2181, Japan.|ALCA, Japan Science and Technology Agency , Tokyo 102-0076, Japan.
authors.forename: Tetsu
authors.identifier: 0000-0002-1355-6775
authors.initials: T
authors.lastname: Mitsumata