Synthesis, structure and electronic properties of noble quasicrystals under high pressure and temperature

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In this research, the LASER-DAC that is the system of the diamond anvil cell combined with the laser heating was used as a very high pressure high temperature synthesis system. First of all, the LASER-DAC system that has used it up to now has been improved. That is, it succeeded in the development of the LASER-DAC system in which the mobile fiber-laser having almost the same wavelength as the YAG and YLF lasers was installed for synthesizing new quasicrystals more easily. In addition, it was also installed instead of the YAG laser of the similar system in the synchrotron radiation facility and made it possible to do in-situ X-ray diffraction measurements under high pressure and temperature. The very high pressure high temperature experiments were tried by using nano polycrystalline diamond anvils that had been developed recently because the expensive natural diamond anvils might become disadvantageous for the new quasicrystal synthesis research under high pressure and temperature. It w … More as found that the mentioned fiber LASER-DAC newly developed in this study was more suitable for heating sample using nano polycrystalline anvils than the previous YAG-LASER-DAC. However, it was also found that very strong diffraction spots from the nano-crystal diamonds was troublesome when the X-ray diffraction experiments. Synthesis of new quasicrystals and relevant compounds and alloys was tried by using the developed fiber LASER-DAC system at high pressure and temperature. It has not arrived to identify new phases by the powder X-ray diffraction measurements and the transmission electron microscope observation although the result with the possibility being synthesized for the material having a new structure was obtained. The phase stability of the compounds and alloys related to quasicrystals was clarified in the cluster level. In addition, phase stability, compression behavior and pressure-induced structural defects were investigated and analyzed by in-situ high pressure powder synchrotron radiation X-ray diffraction measurement at room temperature. Less