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Pressure-Induced Isostructural Phase Transition and Correlation of FeAs Coordination with the Superconducting Properties of 111-Type NaFeAs.

The effect of pressure on the crystalline structure and super-conducting transition temperature (T) of the 111-type NaFeAs system using in situ high-pressure synchrotron X-ray powder diffraction and diamond anvil cell techniques is studied. A pressure-induced tetragonal to tetragonal isostructural p...

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Published in:Journal of the American Chemical Society Vol. 133; no. 20; pp. 7892 - 7897
Main Authors: Qingqing Liu, Xiaohui Yu, Xiancheng Wang, Zheng Deng, Yuxi Lv, Jiillong Zhu, Sijia Zhang, Haozhe Liu, Wenge Yang, Lin Wang, Hokwang Mao, Guoyin Shen, Zhong-Yi Lu, Yang Ren, Zhiqiang Chen, Zhijun Lin, Yusheng Zhao, Changqing Jin
Format: Article
Published: American Chemical Society 5/25/2011
Subjects:
Materials at high pressures
Crystalline electric field
Synchrotron radiation
X-ray diffraction
Diamond anvil cell
Rietveld refinement
Superconductors
Online Access:View this record in EBSCOhost
Summary:The effect of pressure on the crystalline structure and super-conducting transition temperature (T) of the 111-type NaFeAs system using in situ high-pressure synchrotron X-ray powder diffraction and diamond anvil cell techniques is studied. A pressure-induced tetragonal to tetragonal isostructural phase transition was found. The systematic evolution of the FeAs tetrahedron as a function of pressure based on Rietveld refinements on the powder X-ray diffraction patterns was obtained. The nonmonotonic T(P) behavior of NaFeAs is found to correlate with the anomalies of the distance between the anion (As) and the iron layer as well as the bond angle ofAs-Fe-As for the two tetragonal phases. This behavior provides the key structural information in understanding the origin of the pressure dependence of T for 111-type iron pnictide superconductors. A pressure-induced structural phase transition is also observed at 20 GPa.