The intrinsic magnetic topological insulator MnBi2Te4 (MBT) provides a platform for the creation of exotic quantum phenomena. Novel properties can be created by modification of the MnBi2Te4 framework, but the design of stable magnetic structures remains challenging. Here we report ferromagnet-intercalated MnBi2Te4 superlattices with tunable magnetic exchange interactions. Using molecular beam epitaxy, we intercalate ferromagnetic MnTe layers into MnBi2Te4 to create [(MBT)(MnTe)m]N superlattices and examine their magnetic interaction properties using polarized neutron reflectometry and magnetoresistance measurements. Incorporation of the ferromagnetic spacer tunes the antiferromagnetic interlayer coupling of the MnBi2Te4 layers through the exchange-spring effect at MnBi2Te4/MnTe hetero-interfaces. The MnTe thickness can be used to modulate the relative strengths of the ferromagnetic and antiferromagnetic order, and the superlattice periodicity can tailor the spin configurations of the synthesized multilayers.
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The data that support the plots within this paper and other findings of the study are available from the corresponding authors upon reasonable request.
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This work is sponsored by the National Key R&D Program of China under contract no. 2017YFA0305400, the National Natural Science Foundation of China (grants nos. 61874172 and 11904230), the Major Project of Shanghai Municipal Science and Technology (grant no. 2018SHZDZX02), the Shanghai Engineering Research Center of Energy Efficient and Custom AI IC, and the Shanghaitech Quantum Device and Soft Matter Nano-fabrication Labs (SMN180827). X.K. acknowledges support from the Merck POC programme and the Shanghai Rising-Star programme (grant no. 21QA1406000). Y.Y. acknowledges support from Shanghai Pujiang Program (grant no. 20PJ1411500). We acknowledge the facilities, and scientific and technical assistance, of the Australian Microscopy & Microanalysis Research Facility at the Centre for Microscopy and Microanalysis, The University of Queensland. Q.Y. acknowledges support from the Shanghai Sailing Program (grant no. 19YF1433200). We would also like to thank the ISIS neutron facility for the award of beam time (RB2000244, https://doi.org/10.5286/ISIS.E.RB2000244). Certain commercial equipment is identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by NIST. Diamond Light Source is acknowledged for the beam time allocated on I10 under proposal MM30262. B.A. and T.H. acknowledge funding from the Engineering and Physical Sciences Research Council (EP/N032128/1). F.X. was supported by the National Natural Science Foundation of China (52225207 and 52150103), the Shanghai Municipal Science and Technology Major Project (grant no. 2019SHZDZX01), the Program of Shanghai Academic/Technology Research Leader (grant no. 20XD1400200) and the Shanghai Pilot Program for Basic Research—FuDan University 21TQ1400100 (21TQ006).
The authors declare no competing interests.
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Chen, P., Yao, Q., Xu, J. et al. Tailoring the magnetic exchange interaction in MnBi2Te4 superlattices via the intercalation of ferromagnetic layers. Nat Electron 6, 18–27 (2023). https://doi.org/10.1038/s41928-022-00880-1