Li Huan, Wang Yanan, Aoki Yutaro, Nishiyama Saki, Yang Xiaofan, Taguchi Tomoya, Miura Akari, Suzuki Ai, Zhi Lei, Goto Hidenori, Eguchi Ritsuko, Kambe Takashi, Liao Yen-Fa, Ishii Hirofumi, Kubozono Yoshihiro
Research Institute for Interdisciplinary Science, Okayama University Okayama 700-8530 Japan
Department of Physics, Okayama University Okayama 700-8530 Japan.
RSC Adv. 2020 Jul 16;10(45):26686-26692. doi: 10.1039/d0ra04541a. eCollection 2020 Jul 15.
A superconducting KBi sample was successfully prepared using a liquid ammonia (NH) technique. The temperature dependence of the magnetic susceptibility (/) showed a superconducting transition temperature ( ) as high as 3.6 K. In addition, the shielding fraction at 2.0 K was evaluated to be 87%, , a bulk superconductor was realized using the above method. The value was the same as that reported for the KBi sample prepared using a high-temperature annealing method. An X-ray diffraction pattern measured based on the synchrotron X-ray radiation was analyzed using the Rietveld method, with a lattice constant, , of 9.5010(1) Å under the space group of 3̄ (face-centered cubic, no. 227). The lattice constant and space group found for the KBi sample using a liquid NH technique were the same as those reported for KBi through a high-temperature annealing method. Thus, the superconducting behavior and crystal structure of the KBi sample obtained in this study are almost the same as those for the KBi sample reported previously. Strictly speaking, the magnetic behavior of the superconductivity was different from that of a KBi sample reported previously, , the KBi sample prepared using a liquid NH technique was a type-II like superconductor, contrary to that prepared using a high-temperature annealing method, the reason for which is fully discussed. These results indicate that the liquid NH technique is effective and simple for the preparation of a superconducting KBi. In addition, the topological nature of the superconductivity for KBi was not confirmed.
采用液氨（NH）技术成功制备了超导KBi样品。磁化率（/）的温度依赖性显示超导转变温度（ ）高达3.6 K。此外，2.0 K时的屏蔽分数估计为87%， ，使用上述方法实现了体超导体。 值与采用高温退火法制备的KBi样品报道的值相同。基于同步加速器X射线辐射测量的X射线衍射图谱采用Rietveld方法进行分析，在空间群为3̄（面心立方，编号227）下晶格常数 为9.5010(1) Å。使用液氨技术为KBi样品发现的晶格常数和空间群与通过高温退火法报道的KBi的晶格常数和空间群相同。因此，本研究中获得的KBi样品的超导行为和晶体结构与先前报道的KBi样品几乎相同。严格来说，超导的磁行为与先前报道的KBi样品不同， ，使用液氨技术制备的KBi样品是II型超导体，这与使用高温退火法制备的样品相反，对此原因进行了充分讨论。这些结果表明，液氨技术对于制备超导KBi是有效且简单的。此外，未证实KBi超导的拓扑性质。
