{
  "abstract": "Hematite ($α$-Fe$_2$O$_3$) is a prototypical antiferromagnetic platform for high-speed spintronics and magnonics, yet its finite-momentum magnon dynamics and spin-reorientation mechanism remain incompletely understood. Here we use low-wavenumber magneto-Raman spectroscopy to resolve both $k=0$ and finite-$k$ sub-terahertz magnons in $α$-Fe$_2$O$_3$ across the Morin transition. We find that the limiting group velocity $v_0$ remains nearly field independent, whereas the finite-$k$ group velocity $v_{\\mathrm g}$ is strongly modified near the Morin and spin-flop transitions. By combining parallel- and transverse-field measurements with spin-wave modeling, we further extract the temperature-dependent Dzyaloshinskii--Moriya field $H_{\\mathrm D}$ and uniaxial anisotropy fields $H_{\\mathrm{K1}}$ and $H_{\\mathrm{K2}}$. We find that $H_{\\mathrm D}$ is weakly temperature dependent at approximately 2.0--2.3~T, while $H_{\\mathrm{K1}}$ decreases rapidly and $H_{\\mathrm{K2}}$ changes only weakly. This contrast drives the sign reversal of the effective anisotropy field and quantitatively accounts for the Morin transition. Our results establish low-wavenumber Raman spectroscopy as a quantitative probe of finite-momentum antiferromagnetic magnons and provide key material parameters for hematite-based magnonics.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.08030",
  "author_total": 9,
  "authors": [
    {
      "name": "Jiaqi Gong"
    },
    {
      "name": "Yuanzhe Tian"
    },
    {
      "name": "Jun Cui"
    },
    {
      "name": "Meiye Hou"
    },
    {
      "name": "Yuxuan Mu"
    },
    {
      "name": "Di Wang"
    },
    {
      "name": "Xiangang Wan"
    },
    {
      "name": "Di Wu"
    },
    {
      "name": "Qi Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6pa17zjsnhn6f.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.08030",
  "fulltext_url": null,
  "id": "6pa17zjsnhn6f",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.08030",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.08030",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6pa17zjsnhn6f.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:22Z",
      "native_id": "2610.08030",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.08030"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Finite-Momentum Antiferromagnetic Magnon Dynamics across the Morin Transition in Hematite",
  "title_text": "Finite-Momentum Antiferromagnetic Magnon Dynamics across the Morin Transition in Hematite",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:22Z",
  "url": "https://research.draconitic.com/paper/6pa17zjsnhn6f",
  "venue": "arXiv",
  "versions": []
}