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arXiv · 2405.18967

Probing Short-Range Correlations in the van der Waals Magnet CrSBr by Small-Angle Neutron Scattering

Andrey Rybakov·Carla Boix-Constant·Diego Alba Venero·Herre S. J. van der Zant·Samuel Mañas-Valero·Eugenio Coronado
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Abstract

The layered metamagnet CrSBr offers a rich interplay between magnetic, optical and electrical properties that can be extended down to the two-dimensional (2D) limit. Despite the extensive research regarding the long-range magnetic order in magnetic van der Waals materials, short-range correlations have been loosely investigated. By using Small-Angle Neutron Scattering (SANS) we show the formation of short-range magnetic regions in CrSBr with correlation lengths that increase upon cooling up to ca. 3 nm at the antiferromagnetic ordering temperature (TN ~ 140 K). Interestingly, these ferromagnetic correlations start developing below 200 K, i.e., well above TN. Below TN, these correlations rapidly decrease and are negligible at low-temperatures. The experimental results are well-reproduced by an effective spin Hamiltonian, which pinpoints that the short-range correlations in CrSBr are intrinsic to the monolayer limit, and discard the appearance of any frustrated phase in CrSBr at low-temperatures within our experimental window between 2 and 200 nm. Overall, our results are compatible with a spin freezing scenario of the magnetic fluctuations in CrSBr and highlight SANS as a powerful technique for characterizing the rich physical phenomenology beyond the long-range order paradigm offered by van der Waals magnets.

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Andrey Rybakov, Carla Boix-Constant, Diego Alba Venero, Herre S. J. van der Zant, Samuel Mañas-Valero, Eugenio Coronado. 2024-05-29. Probing Short-Range Correlations in the van der Waals Magnet CrSBr by Small-Angle Neutron Scattering. https://doi.org/10.1002/smsc.202400244

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