LaNiO_(3-δ)薄膜中的氧缺位及其对金属输运行为的影响  

Oxygen Deficiency and Its Effect on the Metallic Transport Behavior in LaNiO_(3-δ) Films

作　　者：蔡旭晖 林冠凯 王昊儒 朱弘[1,2] CAI Xuhui;LIN Guankai;WANG Haoru;ZHU Hong(Department of Physics,University of Science and Technology of China,Hefei 230026,China;Key Laboratory of Strongly-Coupled Quantum Matter Physics,Chinese Academy of Sciences,Hefei 230026,China)

机构地区：[1]中国科学技术大学物理系,合肥230026 [2]中国科学院强耦合量子材料物理重点实验室,安徽合肥230026

出　　处：《低温物理学报》2022年第1期33-41,共9页Low Temperature Physical Letters

基　　金：国家自然科学基金(批准号:11674298)资助的课题.

摘　　要：钙钛矿结构LaNiO3因其高电导的金属性输运行为,有望作为电极材料在今后的氧化物器件工艺中发挥重要作用.为了细致认识氧缺位对其金属输运的影响,本文采用溶胶凝胶法在氧气、空气和真空等气氛下烧结获得具有不同缺氧量的LaNiO_(3-δ)薄膜,并利用Mn3+的还原性进一步调整其缺氧量δ.对这些样品的电阻率温度关系测量结果表明,缺氧量δ>0.1后薄膜的高温电阻率开始超过Mott-Ioffe-Regel极限,变成“坏金属”;增大δ至0.2,薄膜的低温剩余电阻率大幅度上升,说明氧空位分布无序性导致的载流子局域化有明显作用.以上样品的金属输运都呈非费米液体行为.继续增加氧缺位浓度,样品电阻率在低温30K以下呈绝缘体温度关系,同时高温金属态转变为费米液体行为,说明钙钛矿结构镍酸盐的金属-绝缘体转变与费米液体输运之间或存在关联性.Thanks to its metallic transport with a high conductivity,perovskite LaNiO_(3) is a promising candidate as the electrode material applying in oxide device technologies in the future.To shed even more light on the influence of oxygen deficiency on the metallic transport,here we report fabrication of the LaNiO_(3-δ) films with different oxygen deficiency levels using the sol-gel method by sintering the gel films under oxygen,air and vacuum ambience,and further adjustment of δ by means of the reducibility of Mn^(3+) ions.The temperature dependence of resistivity for the films reveals that when δ>0.1 the high-temperature saturation of the resistivity begins to exceed the Mott-loffe-Regel limit,displaying a bad metal feature.With increasing δ to 0.2,the low-temperature residual resistivity increases sharply,suggesting the carrier localization induced by the disorder of oxygen vacancies plays an important role.The metallic transport of these LaNiO_(3-δ) films shows the non-Fermi liquid behavior.With further increasing the oxygen deficiency,the film resistivity shows an insulator temperature dependence at temperatures below~30 K,accompanying with the Fermi-liquid transport behavior at high temperatures,suggesting a possible correlation between the metal-insulator transition and Fermi-liquid behavior in the rare-earth nickelates.

关 键 词：非费米液体 氧缺陷 钙钛矿 LaNiO_(3) 

分 类 号：TB383.2[一般工业技术—材料科学与工程]