Native point defects and oxygen migration of rare earth zirconate and stannate pyrochlores  

作　　者：Juanli Zhao Yuchen Liu Yun Fan Wei Zhang Chengguan Zhang Guang Yang Hongfei Chen Bin Liu 

机构地区：[1]School of Materials Science and Engineering,Shanghai University,Shanghai,200444,China

出　　处：《Journal of Materials Science & Technology》2021年第14期23-30,共8页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51602188);the Program for Professor of Special Appointment(Eastern Scholar)by Shanghai Municipal Education Commission(No.TP2015040)。

摘　　要：Various excellent properties of rare earth zirconate and stannate pyrochlores are close related with their native point defects.First-principles calculations are performed to systematically investigate the point defect mechanism and the oxygen diffusion behavior of A_(2)B_(2)O_(7)(A=La,Ce,Pr,Nd,Pm,Sm,Eu,Gd;B=Zr,Sn).The possible defect complexes and their associated reactions under stoichiometric and nonstoichiometric conditions are explored.The O Frenkel pairs are the most stable defect structure in stoichiometric zirconates,whereas the cation antisite defects are the predominant one in stoichiometric stannates.In the case of BO_(2) excess zirconates and stannates,the BA cation antisite defect with the A vacancy and/or the oxygen interstitial is energetically favorable,whereas the ABantisite defect together with the oxygen vacancy and/or the A interstitial is preferable under the A_(2)O_(3) excess condition.Meanwhile,the maximum point defect concentrations of zirconates are much higher than those of stannates.Furthermore,the oxygen migration barriers are similar in these compounds,ranging in 0.68 eV–0.80 eV.The predicted point defects and oxygen diffusion mechanisms play the critical role in their engineering applications and are expected to guide the future property improvement of pyrochlores through the control of point defects and/or composition.

关 键 词：Density-functional theory PYROCHLORE Defect Migration Formation energies 

分 类 号：TQ174.7[化学工程—陶瓷工业]