Research

We are studying the electronic structures of strongly correlated systems by using synchrotron x-ray and laser. Poster (in Japanese)

One of our main experimental techniques is resonant soft x-ray scattering. The following is a schematic diagram of this technique.

We shine x-rays onto a material and measure scattered x-rays from the material, so this is a very simple experiment!

In resonant soft x-ray scattering, we perform x-ray scattering with an x-ray energy near the absorption edges of constituent elements. Therefore, this technique can be considered as a combination of x-ray absorption spectroscopy and x-ray scattering. We need to change the photon energy continuously near the absorption edges, so we definitely need a synchrotron facility as shown in the following figure.  

We mainly use SPring-8 and Photon Factory, but we also have a plan to use other facilities abroad (for example, US, Canada, Switzerland, and Germany). (Please see "links" for details.) The photo below shows our resonant soft x-ray scattering chamber conncted to the ISSP beamline (BL07LSU at SPring-8). The right-hand figure shows the status inside the chamber, where there are x-ray detectors such as PD (photodiode) and MCP (micro-channel plate).

Recently, we have been performing a lot of optical measurements by using laboratory light sources. The photo on the left below is a time-resolved transmittance measurement using a PHAROS laser (1030 nm). The photo on the right is a MOKE microscope that uses LEDs and He-Ne lasers.

The present and future topics are transition-metal compounds such as

♠ charge/orbital/spin-ordered materials

♠ multiferroic materials (which have both magnetism and ferroelectricity),

♠ ferromagnets (where one can control magnetization by laser irradiation),

♠ Li-battery related materials.

Other experimental techniques are

♠ Hard x-ray scattering

♠ X-ray photoemission spectroscopy.

(References)

To study x-ray scattering generally, the following books are useful.

D. Attwood, Soft X-rays and Extreme Ultraviolet Radiation: Principles and Applications (Cambridge University Press, New York, 2000).

J. Als-Nielsen and D. McMorrow, Elements of Modern X-Ray Physics (Wiley, New York, 2001).

You can down load the essence of the first book from the webpage of Prof. David Attwood.

To have an overview of strongly correlated systems, especially transition-metal compounds,

M. Imada, A. Fujimori, and Y. Tokura: Metal-Insulator Transitions, Rev. Mod. Phys. 70 (1998) 1039.

N. Tsuda, K. Nasu, A. Fujimori and K. Siratori: Electronic Conduction in Oxides (Springer-Verlag, Berlin, 2000).

are helpful.