International Workshop on Recent Progress in Superconductivity 2022 （IWRS2022）で招待講演しました。
「International Workshop on Recent Progress in Superconductivity 2022」
＜ 開催日時 ＞
2022年8月9日 ～ 8月11日
＜ 開催場所 ＞
＜ IERS2022 ホームページ ＞
IWRS 2022 (google.com)
＜ 発表内容 ＞
Synthesis Pathway of Superconductive Hydride (Invited)
Superconductivity exceeding 200 K was recently reported in the highly compressed hydrides [1-3]. Here we report the investigation of the superconductivity of them by several synthesis methods. An originally designed transport preparation in the gasket was used in a laser-heating diamond-anvil cell (DAC). In the case of sulfur hydride which was synthesized by a low-temperature pathway (compression at low temperature ~ 200 K) and showed superconductivity with the transition temperature of 200 K at around 150 GPa . We found that the superconductive hydride was synthesized through the chemical reaction of 3H2S → 2H3S + S, by IR laser heating. The in-situ structural confirmation was conducted by using the synchrotron x-ray in SPring-8 . This method, so-called “direct synthesis” opened the new pathway for the synthesis and was widely used for the synthesis of superconducting hydrides, for example, lanthanum-hydrides with elemental hydrogen  and hydrogen source material . Our current experimental detail of the synthesis pathway will be reviewed.
keywords : superconductivity, hydride, laser heating, low temperature, DAC
 A. P. Drozdov et al., “Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system”, Nature 525, 73 (2015).
 A. P. Drozdov et al., “Superconductivity at 250 K in lanthanum hydride under high pressures”, Nature 569, 528 (2019).
 M. Somayazulu et al., “Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures”, Phys. Rev. Lett. 122, 027001 (2019).
 H. Nakao et al., “Superconductivity of Pure H3S Synthesized from Elemental Sulfur and Hydrogen”, J. Phys. Soc. Jpn. 88, 123701 (2019).
* This work was supported by JSPS KAKENHI Grant Number 20H05644.