The novel electronic state of the canted antiferromagnetic (AFM) insulator strontium iridate (Sr2IrO4) is well described by the spin–orbit-entangled isospin Jeff = 1/2, but the role of isospin in transport phenomena remains poorly understood. In this study, antiferromagnet-based spintronic functionality is demonstrated by combining the unique characteristics of the isospin state in Sr2IrO4. Based on magnetic and transport measurements, a large and highly anisotropic magnetoresistance (AMR) is obtained by manipulating the AFM isospin domains. First-principles calculations suggest that electrons whose isospin directions are strongly coupled to the in-plane net magnetic moment encounter an isospin mismatch when moving across the AFM domain boundaries, which generates a high resistance state. By rotating a magnetic field that aligns in-plane net moments and removes domain boundaries, the macroscopically ordered isospins govern dynamic transport through the system, which leads to the extremely angle-sensitive AMR. As this work establishes a link between isospins and magnetotransport in strongly spin–orbit-coupled AFM Sr2IrO4, the peculiar AMR effect provides a beneficial foundation for fundamental and applied research on AFM spintronics.
Bibliographical noteFunding Information:
This work was supported by the NRF Grant (2011-0018306, NRF-2013R1A1A2063904, 2015-001948, NRF-2016R1C1B2013709, NRF-2016R1A2B4016656, NRF-2017K2A9A2A08000278, 2017R1A5A1014862 (SRC program: vdWMRC center), and NRF-2018R1C1B6006859). Computational resources were provided by the Korea Institute of Science and Technology Information Supercomputing Center (Project No. KSC-2017-C3-0027). W.K. was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2018R1D1A1B07050087 and No. 2018R1A6A1A03025340).
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- anisotropic magnetoresistance
- antiferromagnetic spintronics
- perovskite iridates