Atomic origin of spin-valve magnetoresistance at the SrRuO3 grain boundary

Xujing Li; Li Yin; Zhengxun Lai; Mei Wu; Yu Sheng; Lei Zhang; Yuanwei Sun; Shulin Chen; Xiaomei Li; Jingmin Zhang; Yuehui Li; Kaihui Liu; Kaiyou Wang; Dapeng Yu; Xuedong Bai; Wenbo Mi; Peng Gao

doi:10.1093/nsr/nwaa004

Atomic origin of spin-valve magnetoresistance at the SrRuO₃ grain boundary

Natl Sci Rev. 2020 Apr;7(4):755-762. doi: 10.1093/nsr/nwaa004. Epub 2020 Jan 21.

Authors

Xujing Li^{1

2}, Li Yin³, Zhengxun Lai³, Mei Wu^{1

4}, Yu Sheng⁵, Lei Zhang², Yuanwei Sun^{1

4}, Shulin Chen¹, Xiaomei Li², Jingmin Zhang¹, Yuehui Li^{1

4}, Kaihui Liu^{6

7}, Kaiyou Wang^{5

8}, Dapeng Yu^{1

6

9}, Xuedong Bai^{2

7}, Wenbo Mi³, Peng Gao^{1

4

7}

Affiliations

¹ Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China.
² Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
³ Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
⁴ International Center for Quantum Materials, Peking University, Beijing 100871, China.
⁵ State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
⁶ State Key Laboratory for Artificial Microstructure & Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
⁷ Collaborative Innovation Centre of Quantum Matter, Beijing 100871, China.
⁸ College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
⁹ Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

Defects exist ubiquitously in crystal materials, and usually exhibit a very different nature from the bulk matrix. Hence, their presence can have significant impacts on the properties of devices. Although it is well accepted that the properties of defects are determined by their unique atomic environments, the precise knowledge of such relationships is far from clear for most oxides because of the complexity of defects and difficulties in characterization. Here, we fabricate a 36.8° SrRuO₃ grain boundary of which the transport measurements show a spin-valve magnetoresistance. We identify its atomic arrangement, including oxygen, using scanning transmission electron microscopy and spectroscopy. Based on the as-obtained atomic structure, the density functional theory calculations suggest that the spin-valve magnetoresistance occurs because of dramatically reduced magnetic moments at the boundary. The ability to manipulate magnetic properties at the nanometer scale via defect control allows new strategies to design magnetic/electronic devices with low-dimensional magnetic order.

Keywords: electron microscopy; grain boundary; magnetic defects; spin-valve.