Negative thermal expansion of Ca2RuO4 with oxygen vacancies

作     者：Sen Xu Yangming Hu Yuan Liang Chenfei Shi Yuling Su Juan Guo Qilong Gao Mingju Chao Erjun Liang 徐森;胡杨明;梁源;史晨飞;苏玉玲;郭娟;高其龙;晁明举;梁二军

作者机构：Key Laboratory of Materials Physics of Education of ChinaSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450001China Department of Applied PhysicsDonghua UniversityShanghai 201620China School of Physics and Electronic EngineeringZhengzhou University of Light IndustryZhengzhou 450001China 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2020年第29卷第8期

页      面：393-399页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：the National Natural Science Foundation of China(Grant Nos.11874328 and 11574276) The SXRD experiments were performed at the BL02B2 and BL04B2 of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute(JASRI proposal Nos.2019A1167,2019A1095,and 2019A1340) We also acknowledge the help of Beamline Scientists Dr.Lirong Zheng(BSRF),Dr.Shogo Kawaguchi,and Dr.Koji Ohara(SPring-8) 

主　　题：negative thermal expansion structure oxygen vacancies metal-insulator transition octahedra distortion 

摘      要：Oxygen vacancies have a profound effect on the magnetic,electronic,and transport properties of transition metal oxides but little is known about their effect on thermal *** we report the effect of oxygen defects on the structure formation and thermal expansion properties of the layered perovskite Ca2RuO4(CRO).It is shown that the CRO containing excess oxygen crystallizes in a metallic L-CRO phase without structure transition from 100 K to 500 K and displays a normal thermal expansion behavior,whereas those with oxygen vacancies adopt at room temperature an insulating S-CRO phase and exhibit an enormous negative thermal expansion(NTE)from 100 K to about 360 K,from where they undergo a structure transition to a high temperature metallic L-CRO *** to the L-CRO containing excess oxygen,the S-CRO structure has increasingly large orthorhombic strain and distinctive in-plane distortion upon *** in-plane distortion of the RuO6 octahedra reaches a maximum across 260 K and then relaxes monotonically,providing a structure evidence for the appearance of an antiferromagnetic orbital ordering in the paramagnetic phase and the A_g phonon mode suppression and phase flip across the same temperature found *** the L-and S-CRO display an antiferromagnetic ordering at about 150-110 K,with ferromagnetic ordering components at lower *** NTE in S-CRO is a result of a complex interplay among the spin,orbital,and lattice.