Spontaneous Hall effect induced by collinear antiferromagnetic order at room temperature

Abstract

Magnetic information is usually stored in ferromagnets, where the ‚Üë and ‚Üì spin states are distinguishable due to time-reversal symmetry breaking. These states induce opposite signs of the Hall effect proportional to magnetization, which is widely used for their electrical read-out. By contrast, conventional antiferromagnets with a collinear antiparallel spin configuration cannot host such functions, because of \({\mathcal{T}}{\mathrm{t}}\) symmetry (time-reversal \({\mathcal{T}}\) followed by translation t symmetry) and lack of macroscopic magnetization. Here we report the experimental observation of a spontaneous Hall effect in the collinear antiferromagnet FeS at room temperature. In this compound, the ‚Üë‚Üì and ‚Üì‚Üë spin states induce opposite signs of the spontaneous Hall effect. Our analysis suggests that this does not reflect magnetization, but rather originates from a fictitious magnetic field associated with the \({\mathcal{T}}{\mathrm{t}}\)-symmetry-broken antiferromagnetic order. The present results pave the way for electrical reading and writing of the ‚Üë‚Üì and ‚Üì‚Üë spin states in conductive systems at room temperature, and suggest that \({\mathcal{T}}{\mathrm{t}}\)-symmetry-broken collinear antiferromagnets can serve as an information medium with vanishingly small magnetization.