Japan-CIS joint project for optical studies of new materials

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During this research project, we invited 4 Russian scientists and 1 Uzbekistan scientist and send 4 Japanese scientists to Russia, Latovia, and Estonia.A Uzbekistan young scientist sponsored by JSPS also joined this research project. Through this exchange program, we focused on the research on solid fullerenes and related compounds.One of our achievement is the discovery of a new superconducting ternary compound, Na-N-C_<60>, which is the first Na-containing superconductor. After the effort to improve the synthetic method, the structure and superconducting properties were characterized by X-ray diffraction, SQUID magnetometer, ESR,and low-filed microwave absorption. We proposed that the superconductivity was brought about by the nitrogen species which protects the disproportionation phase separation. Based on this successful result, we expanded the ternary compound involving C_<60>.The first one was prepared by the alkali-metal doping of the charge-transfer compound between organic-don … More or and C_<60>.We found a superconductivity in the materials doped at a moderate temperature slightly higher than room temperature. The doping of alkali-metal to the poly-alkey-thiophene C_<60> system showed a multi-phase superconductivity.The luminescence experiments of C_<60>, C_<60>F_<48> and C_<70>F_<58> was carried out under VUV excitation (undulator of beam line 3A1) from the UVSOR electron storage rings of IMS.The luminescence intensity showed a clear jump at the phase transition temperature which means that the effect of crystal field is very strong although the excited state is a Frenkel type. On the other hand the luminescence of C_<60>F_<48> and C_<70>F_<58> showed a complicated relaxation process.Combined with the experiment of the excimer laser excitation, it was concluded that the luminescence consists of three components in the decay curve. Most interestingly, the luminescence intensity decreased with the irradiation of the undulator radiation . It was evidenced that this phenomenon is related to the photo-dissociation process such as the cleavage of CF.More detailed analysis of the relaxation process is in progress. Less