Dr. Yo Tokunaga, Advanced Science Research Center, JAEA, Japan

I did my postdoc research in LNCMI-Grenoble twelve years ago. It was my first experience staying in Europe, and now I understand that all the scientific activities and the time I spent at this very international laboratory laid down a good foundation for my career as a researcher. This year I was able to come back to LNCMI-Grenoble as a guest researcher for one year.

 My research field is solid state physics, and in the last decade I have focused on the electronic states of f-electron systems. Important characteristics of correlated f‐electrons are their dual nature of having aspects of both localization and itinerancy, and strong spin-orbit coupling producing multipolar degrees of freedom. These characteristics cause a large variety of exotic phases such as heavy fermion, unconventional superconductivity, multipolar ordering and quantum criticality. A high magnetic field is definitely an important parameter for seeking and tuning these new phases. The field-induced, reentrant superconductivity discovered in ferromagnetic superconductors is an excellent example that shows the importance of high magnetic fields in this research area.    

To explore these exotic phases in solids I am using NMR spectroscopy, which is an extraordinarily powerful microscopic probe of electronic properties. At LNCMI-Grenoble I have access to the best NMR techniques and instrumentation, provided by the people in the laboratory, and I still learn a lot from them every time I visit Grenoble. We are currently studying the mechanism of the field-induced, reentrant superconductivity by means of NMR.