Correlated perovskite nickelates with valence variable rare-earth compositions  

作　　者：Hao Zhang Yi Bian Yuxuan Xia Yuchen Cui Ziang Li Fang Zhang Yiming Bai Nuofu Chen Jikun Chen 

机构地区：[1]School of New Energy,North China Electric Power University,Beijing,102206,China [2]School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing,100083,China

出　　处：《Journal of Rare Earths》2024年第4期743-748,共6页稀土学报（英文版）

基　　金：Project supported by the National Key Research and Development Program of China(2021YFA0718900);the National Natural Science Foundation of China(62074014,52073090)。

摘　　要：While the metal to insulator transition(MIT)of d-band correlated perovskite nickelates(RENiO_(3))are widely adjustable via their rare-earth composition,the roles of potential valence variabilities associated with the rare-earth elements were rarely concerned.Herein,we demonstrate the material synthesis and MIT properties of RENiO_(3) containing valence variable rare-earth compositions,such as Ce,Pr,Sm,Eu and Tb.The metastable perovskite structure of SmNiO_(3) and EuNiO_(3) with a rare-earth valence states variable towards+2 can be effectively synthesized under high oxygen pressures as it is necessary to reduce their formation free energies.This is in contrast to Ce and Tb,in which situations the variable rare-earth valence state towards+4 reduces their ionic radius and prohibits their occupation or co-occupation of the rare-earth site within the perovskite structured RENiO_(3).Nevertheless,PrNiO_(3) with MIT properties can be effectively synthesized at lower oxygen pressures,owing to the higher stability to form a fully occupied 6s orbit associated Pr3+compared to the half-filled one related to Pr4+.The present work provides guidance for regulating the MIT properties of RENiO_(3).

关 键 词：Metal to insulator transition Metastable perovskites Rare-earth nickelates OXIDES 

分 类 号：TB34[一般工业技术—材料科学与工程]