FeSe的输运和钉扎性质（英文）

发布时间：2019-02-20 07:29

【摘要】：利用固相反应法合成了FeSe超导体,根据名义组分和热处理工艺的不同共得到四组FeSe样品,利用X射线衍射仪(XRD)和物性测试系统(PPMS)分别对样品的晶体结构和电输运性能进行表征,并分析了磁通钉扎特性.XRD测试结果表明所有的样品主相均为β-FeSe四方相,同时在样品中也存在少量杂相,包括α-FeSe和Fe,不同名义组分和不同热处理工艺对晶体结构的影响较小.电阻率测试结果表明所有的样品均发生了超导转变,Tc大约为9K,在零场下的转变宽度约为3K,但是四个样品的正常态电阻率明显不同,通过测试四个样品在不同磁场下的电阻率随温度的变化曲线,随着磁场的增加,电阻率曲线出现展宽效应,分析表明FeSe的磁通钉扎行为是由于在不同磁场下热激活磁通蠕动引起的,其上临界磁场可达23T.
[Abstract]:FeSe superconductors were synthesized by solid state reaction. Four groups of FeSe samples were obtained according to the nominal composition and heat treatment process. The crystal structure and electrical transport properties of the samples were characterized by X-ray diffractometer (XRD) and physical property measurement system (PPMS), and the magnetic flux pinning characteristics were analyzed. The results of XRD showed that all the main phases of the samples were 尾-FeSe tetragonal phase. At the same time, a small amount of heterogenous phases also exist in the samples, including 伪-FeSe and Fe, different nominal components and different heat treatment processes have little effect on the crystal structure. The results of resistivity measurement show that all the samples have superconductivity transition, the Tc is about 9K and the transition width is about 3K at zero field, but the normal state resistivity of the four samples is obviously different. The resistivity curves of the four samples under different magnetic fields were measured, and the broadening effect was observed with the increase of the magnetic field. The results show that the flux pinning behavior of FeSe is caused by the peristalsis of heat activated flux in different magnetic fields, and the upper critical magnetic field can reach 23T.
【作者单位】：西南交通大学超导与新能源研究开发中心材料先进技术教育部重点实验室超导与新能源研究开发中心;新南威尔士大学材料科学与工程学院;
【基金】：Project supported by the Fundamental Research Funds for the Central Universities(Grant No.2682015CX008,2682015ZT11) the financial support of Li Jinsheng scholarship of Superconductivity and New Energy R&D Center~~
【分类号】：O511.3

【相似文献】