1. 연수기간 : 2021. 11. 21 ~ 2021. 11. 25 (총 4박 5일)
2. 연수국가 : 온라인 진행
3. 연수기관명 : KVS (The Korean Vacuum Society)
4. 연수자 : 석박사통합과정 7기 참여대학원생 1명
5. 연수주제 : Contribution of Hydrogen for Superconducting Temperatures of TiZr Alloys under High Pressure
TiZr alloys absorb a large amount of hydrogen and have technical usefulness for renewal energy storage applications. Due to the complete solubility of Ti and Zr atoms in a structural phase diagram together with a high affinity of hydrogen, TiZr alloys are good candidates for forming polyhydries under high hydrogen pressure. They are also expected to exhibit enhanced temperature for superconductivity (Tc) induced by a strong electron-phonon coupling. To investigate the change of Tc as a function of pressure, pieces of TiZr and hydrogenated TiZr alloys were prepared, and the electric resistivity and structural data were measured under high pressure created by using a diamond anvil cell. The Tc values for TiZr alloy increased with increasing pressure from 2.7 K to 11.7 K at 5.4 GPa, 50 GPa, respectively. The Tc values for hydride TiZr increased from 3.4 K to 9.4 K at 6 GPa and 32 GPa, respectively, but decreased to 8 K with increasing pressure further to 55 GPa. The detailed analysis of synchrotron X-ray diffraction studies revealed that the structures of both TiZr and hydride TiZr samples changed from an hcp (a=3.23 Å, c=5.15 Å) at ambient to bcc (a=3.20 Å ) at 50 GPa through -phase (a=4.84 Å, c=3.02 Å) starting near 15 GPa. A small fraction of Ti(Zr)H2 phase (Laves phase, a=3.60 Å, c=5.51 Å) was found from hydride TiZr sample at ambient condition but an effect for the Tc was negligible. Instead, the reduced Tc with increasing pressure for hydrogenated samples is believed to responsible for the limited contribution of electron-phonon coupling which was suppressed by the strong binding of host elements with hydrogen atoms. The detailed results of electric resistivity measurements combined with structural analysis for pure and hydrogenated TiZr alloys under high pressure will be presented.