共振X射线衍射研究高温超导Sr2CuO3.4晶体中的调制结构  

Resonant X-ray diffraction studies on modulation structures of high temperature superconducting sample Sr2CuO3.4

作　　者：王海波[1,2] 罗震林[2] 刘清青[3] 靳常青[3] 高琛[2] 张丽[1] Wang Hai-Bo;Luo Zhen-Lin;Liu Qing-Qing;Jin Chang-Qing;Gao Chen;Zhang Li(Tonghua Normal University, Tonghua 134002, China;University of Science and Technology of China, Hefei 230026, China;Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China)

机构地区：[1]通化师范学院,通化134002 [2]中国科学技术大学,合肥230026 [3]中国科学院物理研究所,北京100190

出　　处：《物理学报》2019年第18期274-278,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:WK2310000043);吉林省教育厅“十三五”科学技术课题(批准号:JJKH20180860KJ)资助的课题~~

摘　　要：为了进一步研究Sr2CuO3.4高温超导样品中调制结构与超导电性关系,本文对其调制结构形成机制提出了一种新的解释.采用同步辐射共振X射线衍射技术在Cu K边附近探测调制结构随入射光能量的变化,探测到Cu^2+,Cu^3+变价有序,并用于解释Sr2CuO3.4高温超导样品中调制结构的形成机制.实验结果表明,氧空位既占据顶角位置又存在于CuO2面内,氧空位的有序排布造成变价铜离子有序,这种有序结构与其超导电性相关.Sr2CuO3+δ is cuprate, a high temperature superconducting (HTS) material that has a single copper oxide layer and a relatively high critical temperature. Its structure is simple and contains fewer atoms, but there are many modulation structures in it. A lot of studies have pointed out that the modulation structure is related to its superconductivity. In order to further study the relationship between modulated structure and superconductivity in Sr2CuO3.4 HTS sample, a new explanation for the formation mechanism of modulation structure is proposed in this paper. The synchrotron radiation resonant X-ray diffraction (RXD) technique is used to detect the variation of modulation structure near the absorption edge of Cu atom. Cu^2+, Cu^3+ valence order is detected and used to explain the formation mechanism of modulation structure in Sr2CuO3.4 high temperature superconducting sample. The energy values of incident light are selected to be 8.52, 8.95, 8.98, 9.05, 9.5, and 10.0 keV near the edge of Cu K. The energy resolution is about 1.5 eV. The detector used in the experiment is Mar165 CCD surface detector. The distance from the detector to the sample is about 315 mm. The two-dimensional diffraction pattern recorded by the CCD plane detector is processed by Fit2D software to obtain the diffraction integral intensity. In addition, the energy calibration for each of the copper foil samples is carried out prior to the start of the experiment and in the process of varying energy value. The experimental results show that the Bragg diffraction peaks corresponding to Tc = 48 K and the modulation structures of Fmmm and Pmmm are visible and calibrated. The intensity of the corresponding (2/5, 4/5, 0) diffraction peak of Fmmm is energy-dependent near the Cu K edge and first increases and then decreases abruptly near the absorption edge. This indicates that a stable ordered arrangement structure of Cu^2+ and Cu^3+ is formed at this time. The weak diffraction signal of this ordered arrangement structure confirms the fact that the c

关 键 词：高温超导 调制结构 共振X射线衍射 同步辐射 

分 类 号：O511.3[一般工业技术—材料科学与工程]