Crystal structure instability of FeSe grains: Formation of non-superconducting phase at the grain surface
Crystal structure instability of FeSe grains: Formation of non-superconducting phase at the grain surface
复制标题
DOI：
10.7567/jjap.55.053101
复制
发表时间：
2016-05-01
影响因子：
1.5
通讯作者：
Miura, Osuke
中科院分区：
文献类型：
--
作者：
Izawa, Hiroki;Tanaka, Yuji;Miura, Osuke
研究了不同晶粒尺寸的FeSe多晶样品的磁化性能和晶体结构。对于晶粒较大的样品，磁性临界电流密度J(c)较大。对于晶粒较小的样品，没有观察到超导信号；相反，观察到磁化迟滞，这不是超导的结果。在小晶粒样品的x射线衍射图中，观察到宽附加峰，对应于FeSe晶粒表面非超导（单斜）Fe-Se相的形成。晶粒表面的晶体结构不稳定可能是目前所研究的硫系铁多晶线超导性能低的原因。(C) 2016 .日本应用物理学会
We investigated the magnetization and crystal structure of FeSe polycrystalline samples with various grain sizes. For the samples with large grains, a large magnetic critical current density J(c) was observed. For the samples with small grains, superconductivity signals were not observed; instead, magnetization hysteresis, which is not a result of superconductivity, was observed. In the X-ray diffraction pattern for the samples with small grains, broad additional peaks were observed, corresponding to the formation of the non-superconducting (monoclinic) Fe-Se phase at the FeSe grain surface. The crystal structure instability at the grain surface would be the reason for the low superconducting properties of the Fe-chalcogenide polycrystalline wires investigated thus far. (C) 2016 The Japan Society of Applied Physics