The magnetic properties of the van der Waals magnetic topological insulators ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ and ${\mathrm{MnBi}}_4{\mathrm{Te}}_7$ 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.

• Received 8 January 2020
• Revised 27 February 2020
• Accepted 14 April 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.197201