Elucidation of Alignment Process of Micro-Particles by Neutrons

Direct Observation of Alignment Process of Fine Ceramic Particles Realized by Neutron Diffraction

2008.03.19

National Institute for Materials Science
Japan Atomic Energy Agency

In joint research, a team headed by Researcher Noriki Terada of the Quantum Beam Center, National Institute for Materials Science and a team led by Naoto Metoki, a Research Officer at the Advanced Science Research Center, Japan Atomic Energy Agency succeeded in direct observation of the process of alignment of feeble magnetic fine particles dispersed in a solvent by a magnetic field in a neutron scattering experiment using the JAEA’s research reactor JRR-3.

Abstract

  1. In joint research, a team headed by Researcher Noriki Terada of the Quantum Beam Center, National Institute for Materials Science (President: Prof. Teruo Kishi) and a team led by Naoto Metoki, a Research Officer at the Advanced Science Research Center, Japan Atomic Energy Agency (hereinafter, JAEA; President: Toshio Okazaki) succeeded in direct observation of the process of alignment of feeble magnetic fine particles dispersed in a solvent by a magnetic field in a neutron scattering experiment using the JAEA’s research reactor JRR-3.
  2. Among ceramics, alumina materials are widely used due to their excellent electrical insulating properties, heat resistance, mechanical properties, thermal conductivity, and optical properties. These properties are further improved by alignment of the alumina fine particles which make up alumina materials in a designated direction under a strong magnetic field environment. However, in order to achieve more perfect alignment by the magnetic field, an elucidation of the fine particle alignment process was needed.
  3. In this work, the researchers succeeded for the first time in observing the alignment process of alumina fine particles dispersed in a solvent under magnetic fields up to 10T in neutron scattering experiments using the multipurpose thermal neutron beamport (Musashi) installed in the JAEA’s JRR-3 research reactor. The results revealed that a high field exceeding 20T is necessary for full orientation of alumina fine particles.
  4. These results are the first example of direct observation of the process of orientation of feeble magnetic fine particles in a magnetic field, and demonstrate that neutron diffraction is an effective method of direct observation of the alignment process of fine particles. Because it is possible to grasp the magnetic field orientation process in specimens as a whole by using neutrons, which have a high capacity to pass through substances in comparison with X-rays, elucidation of the fine particle orientation processes in various materials by neutron diffraction is expected in the future.
  5. These research results are scheduled for publication in the March 24 issue of the American scientific journal, "Applied Physics Letters."
"Fig:Embedded resin for cross-sectional observation" Image

Fig:Embedded resin for cross-sectional observation