Meta-magnetism of weakly-coupled antiferromagnetic topological insulators

The magnetic properties of the van der Waals magnetic topological insulators MnBi2Te4 and MnBi4Te7 are investigated by magnetotransport measurements. We evidence that the relative strength of the interlayer exchange coupling J to the uniaxial anisotropy K controls a transition from an A-type antiferromagnetic order to a ferromagneticlike metamagnetic state. A bilayer Stoner-Wohlfarth model allows us to describe this evolution, as well as the typical angular dependence of specific signatures, such as the spin-flop transition of the uniaxial antiferromagnet and the switching field of the metamagnet.

Phys. Rev. Lett. 124, 197201 (2020)

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