Direct visualization of surface spin-flip transition in MnBi4Te7

Abstract

We report direct visualization of spin-flip transition of the surface layer in antiferromagnet MnBi4Te7, a natural superlattice of alternating MnBi2Te4 and Bi2Te3 layers, using cryogenic magnetic force microscopy (MFM). The observation of magnetic contrast across domain walls and step edges confirms that the antiferromagnetic order persists to the surface layers. The magnetic field dependence of the MFM images reveals that the surface magnetic layer undergoes a first-order spin-flip transition at a magnetic field that is lower than the bulk transition, in excellent agreement with a revised Mills' model. Our analysis indicates an enhancement of the order parameter in the surface magnetic layer, implying robust ferromagnetism in the single-layer limit. The direct visualization of surface spin-flip transition not only opens up exploration of surface metamagnetic transitions in layered antiferromagnets, but also provides experimental support for realizing quantized transport in ultra-thin films of MnBi4Te7 and other natural superlattice topological magnets.

6 pages, 4 figures

References in corpus (11)

• High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator
• Antiferromagnetic topological insulators
• The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3
• Precise quantization of anomalous Hall effect near zero magnetic field
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• Robust A-type order and spin-flop transition on the surface of the antiferromagnetic topological insulator MnBi${}_2$Te${}_4$
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• Magnetic imaging of antiferromagnetic domain walls
• Direct evidence of ferromagnetism in MnSb2Te4
• Unusual dynamic susceptibility arising from soft ferromagnetic domains in MnBi8Te13 and Sb-doped MnBi2nTe3n+1 (n=2, 3)
• Coexisting Ferromagnetic-antiferromagnetic Phase and Manipulation in Magnetic Topological Insulator MnBi4Te7

Cited by in corpus (8)

• Layer-by-layer disentanglement of Bloch states via frequency-domain photoemission
• Quantum anomalous Hall effects controlled by chiral domain walls
• Magnetically Modulated Electrical Switching in an Antiferromagnetic Transistor
• Symmetry-driven anisotropic coupling effect in antiferromagnetic topological insulator: Mechanism for high-Chern-number quantum anomalous Hall state
• Electrostatic effects of the MnBi2Te4-superconductor hetero-structures in chiral Majorana search
• Tailoring Neel orders in Layered Topological Antiferromagnets
• Role of non-magnetic spacers in the magnetic interactions of antiferromagnetic topological insulators MnBi${}_4$Te${}_7$ and MnBi${}_2$Te${}_4$
• Topological properties of domain walls in antiferromagnetic topological insulators