The enhanced negative thermal expansion in less-oxygen-vacancies copper pyrophosphate  

作　　者：L.Lu Xie T.Fei Shi J.Chao Lin X.Kai Zhang X.Kang Zhong K.Ke Liu B.Ke Dong Cheng Yang X.Lian Wang T.Jiao Xiong W.Sheng Yan J.Ping Xu H.Can Chen Wen Yin Ming Li Peng Tong W.Hai Song Y.Ping Sun 

机构地区：[1]Key Laboratory of Materials Physics,Institute of Solid State Physics,HFIPS,Chinese Academy of Sciences,Hefei 230031,China [2]University of Science and Technology of China,Hefei 230026,China [3]Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions,High Magnetic Field Laboratory,HFIPS,Chinese Academy of Sciences,Hefei 230031,China [4]Spallation Neutron Source Science Center,Dongguan 523803,China [5]Department of Chemistry,University of Warsaw,02093 Warsaw,Poland [6]National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230029,China

出　　处：《Journal of Materials Science & Technology》2023年第15期80-85,共6页材料科学技术（英文版）

基　　金：supported by the National Natural Foundation of China(No.52171146 and No.U1932127);Natural Science Foundation of Anhui Province(No.2108085ME145);the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS)(No.QYZDB-SSW-SLH015)。

摘　　要：For oxides,controlling the concentration of oxygen vacancy is a useful way to optimize their functional properties.However,when it comes to the field of negative thermal expansion(NTE),much less attention has been paid to the effect of oxygen vacancy on NTE,though oxide-typed NTE materials account for more than 40%of the total NTE materials.Here,we report that the linear coefficient of thermal expansion at 250–350 K of copper pyrophosphate(i.e.,Cu_(2)P_(2)O_(7))can be significantly improved from–13.88 to–36.60 ppm/K when the synthesis temperature is raised from 1073 to 1373 K.The combined study including X-ray absorption near edge structure,neutron powder diffraction,and X-ray diffraction has confirmed the selective vacancies in the O1 site for low-temperature synthesized samples,which suppress both the phase-transition and framework-structure driven NTE simultaneously.Our result proposes a new approach for optimizing the NTE effect of oxides.

关 键 词：Negative thermal expansion XANES Oxygen vacancy Oxide Lattice distortion Phase transition 

分 类 号：TB34[一般工业技术—材料科学与工程]