Multiphase cooperation for multilevel strain accommodation in a single-crystalline BiFeO_(3) thin film  

作　　者：Wooseon Choi Bumsu Park Jaejin Hwang Gyeongtak Han Sang-Hyeok Yang Hyeon Jun Lee Sung Su Lee Ji Young Jo Albina Y.Borisevich Hu Young Jeong Sang Ho Oh Jaekwang Lee Young-Min Kim 

机构地区：[1]Department of Energy Science,Sungkyunkwan University(SKKU),Suwon 16419,Republic of Korea [2]Samsung Electronics,Hwaseong 18448,Republic of Korea [3]Department of Physics,Pusan National University,Busan 46241,Republic of Korea [4]LG Energy Solution,Daejeon 34122,Republic of Korea [5]Department of Materials Science and Engineering,Kangwon National University,Republic of Korea [6]School of Materials Science and Engineering,Gwangju Institute of Science and Technology(GIST),Gwangju 61005,Republic of Korea [7]Center for Nanophase Materials Sciences,Oak Ridge National Laboratory,TN 37831,USA [8]Graduate School of Semiconductor Materials and Devices Engineering,Ulsan National Institute of Science and Technology(UNIST),Ulsan 44919,Republic of Korea [9]Department of Energy Engineering,KENTECH Institute for Energy Materials and Devices,Korea Institute of Energy Technology(KENTECH),Naju 58330,Republic of Korea

出　　处：《Chinese Physics B》2024年第9期57-66,共10页中国物理B（英文版）

基　　金：Samsung Research Fundings&Incubation Center of Samsung Electronics(Grant No.SRFCMA1702-01);Y.-M.K acknowledges partial support from the National Research Foundation of Korea(NRF)(Grant No.2023R1A2C2002403)funded by the Korean government in Korea;A.Borisevich acknowledges support from FaCT,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Science,Collaboratives Research Division.

摘　　要：The functionalities and diverse metastable phases of multiferroic BiFeO_(3)(BFO)thin films depend on the misfit strain.Although mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is unclear whether a singlecrystalline BFO thin film can accommodate misfit strain without the involvement of its polymorphs.Thus,understanding the strain relaxation behavior is key to elucidating the lattice strain–property relationship.In this study,a correlative strain analysis based on dark-field inline electron holography(DIH)and quantitative scanning transmission electron microscopy(STEM)was performed to reveal the structural mechanism for strain accommodation of a single-crystalline BFO thin film.The nanoscale DIH strain analysis results indicated a random combination of multiple strain states that acted as a primary strain relief,forming irregularly strained nanodomains.The STEM-based bond length measurement of the corresponding strained nanodomains revealed a unique strain accommodation behavior achieved by a statistical combination of multiple modes of distorted structures on the unit-cell scale.The globally integrated strain for each nanodomain was estimated to be close to1.5%,irrespective of the nanoscale strain states,which was consistent with the fully strained BFO film on the SrTiO_(3) substrate.Density functional theory calculations suggested that strain accommodation by the combination of metastable phases was energetically favored compared to single-phase-mediated relaxation.This discovery allows a comprehensive understanding of strain accommodation behavior in ferroelectric oxide films,such as BFO,with various low-symmetry polymorphs.

关 键 词：BiFeO_(3) scanning transmission electronmicroscopy electron holography multiferroic material strain mapping 

分 类 号：TB383.2[一般工业技术—材料科学与工程]