BCMaterials invited talks: Professor Tetsuya Nakamura

Structural and magnetic properties of materials and the related synchrotron X-ray techniques at SPring-8

Prof. Tetsuya Nakamura Center for Synchrotron Radiation Research Japan Synchrotron Radiation Research Institute (JASRI)

In the 1970s, X-rays were thought to be practically useless for studies of magnetism in comparison with neutrons due to their smaller cross-section with magnetic spins. However, in the last three decades synchrotron X-rays have become a popular characterization tool for investigating magnetic properties of materials in addition to their crystal structures. In particular, outstanding progress has been made with the X-ray magnetic circular dichroism (XMCD) measurement technique in comparison to other synchrotron based magnetic probes. In this talk, after a brief introduction to XMCD spectroscopy, I will present some recent XMCD studies and their related technical developments which have been achieved at SPring-8. These include the soft XMCD measurement technique using a pulse magnet generating 40 T [1] and the scanning soft XMCD microspectroscopy under high magnetic fields up to 8 T [2] and results from some demonstrative studies including the magnetic-field-induced valence transition phenomenon in Eu compounds [3] and magnetic domain observations in Nd-Fe-B permanent magnets [4]. I also plan to provide a perspective of the future experimental techniques that are expected at synchrotron facilities.

[1] T. Nakamura et al., Appl. Phys. Express 4, 066602 (2011). [2] Y. Kotani et al., J. Synchrotron Rad. 25, 1444 (2018). [3] T. Nakamura et al., J. Phys. Soc. Jpn. 81, 10375 (2012). [4] D. Billington et al., Phys. Rev. Mater. 2, 104413 (2018). Prof. Tetsuya Nakamura                   Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI)

Tetsuya Nakamura (TN) is a chief scientist of the Japan Synchrotron Radiation Research Institute (JASRI) and leader of the Spectroscopic Analysis Group II at SPring-8. TN is also a visiting professor of Institute for Materials Research, Tohoku University. His main research involves the study of magnetic materials using X-ray magnetic circular dichroism (XMCD) and the development of measurement techniques and the necessary instrumentation. TN obtained his PhD in material science at the University of Tokyo in 1998. He was a postdoctoral fellow at RIKEN for about three years, and then became an assistant professor at the Institute of Industrial Science, University of Tokyo until Oct. 2002. For the last 16 years, TN has been a scientist at JASRI who is mainly in charge of the soft X-ray beamline BL25SU. He is also a principal investigator for two large projects involving the development of high-performance permanent magnets. TN has contributed to over 150 publications, and has given 10 invited talks at international conferences in the last 5 years.