Emergent ferromagnetism and unusual irreversible magnetoresistance in an intercalated van der Waals antiferromagnet.

Zhai, Zixin; Liu, Wenhao; Guo, Xiaoyu; Schulze, Daniel J; Kuo, Ting-Wei; Agarwal, Nishkarsh; Stangel, Alex; Joshi, Pramanand et al. · Proc Natl Acad Sci U S A · 2026

basic_science · Level V

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Abstract

Orthorhombic air-stable two-dimensional (2D) antiferromagnet (AFM) CrSBr has attracted much research interest lately thanks to its rich magnetic behaviors together with its remarkable electronic, excitonic, and polaritonic properties. Here, we report a reliable electrochemical intercalation method by inserting large tetrabutylammonium (TBA<sup>+</sup>) ions into CrSBr layers. Magnetically, such intercalation efficiently suppresses the interlayer AFM and induces a ferromagnetic (FM) order with a much-enhanced transition temperature up to 200 K, nearly 70 K higher than the AFM onset of 132 K in pristine CrSBr. Electronically, the TBA<sup>+</sup> intercalation not only increases the electric conductivity of CrSBr, which is further enhanced by magnetic fields, but also introduces a giant negative irreversible magnetoresistance. This work demonstrates the tunable magnetic and electronic properties of CrSBr as well as their interplay, paving the way for advanced spintronic and magnetic memory devices.