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arXiv · 2603.05755

Exchange anisotropy-driven noncollinear magnetism and magnetic transitions in MnTiO3 ilmenite

Srimal Rathnayaka·Luke Daemen·Despina Louca
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Abstract

Evidence for multiple magnetic transitions and unconventional spin exchange interactions in the ilmenite insulator MnTiO3 is provided via neutron scattering. On cooling, while G-type antiferromagnetic (AFM) order sets in first at 63 K with a k1 = (000) characteristic wave vector, a weaker second magnetic transition with k2 = (00 3/2 ) appears near 42 K, giving rise to a noncollinear structure. Intrinsic buckling of the honeycomb lattice along c creates bond anisotropy and a distorted crystal field that can lead to exchange paths that modulate orbital overlap and spin-orbit coupling. The inelastic spectrum is best described by magnetic exchange anisotropy that breaks the local symmetry of the honeycomb, with competing AFM Heisenberg, Dzyaloshinskii-Moriya and alternate intra-planar ferromagnetic (FM) interactions, that may yield a weakly-coupled ladder system.

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Srimal Rathnayaka, Luke Daemen, Despina Louca. 2026-03-05. Exchange anisotropy-driven noncollinear magnetism and magnetic transitions in MnTiO3 ilmenite. https://arxiv.org/abs/2603.05755

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