{
  "abstract": "The magnetic properties of Sm-based intermetallics are governed by a delicate interplay between localized $4f$ states, exchange interactions, and valence fluctuations, yet the role of dynamical $4f$ correlations remains poorly understood. Here we investigate the electronic structure and magnetic anisotropy of SmCo$_5$ and SmCu$_5$ using self-consistent DFT+$U$(ED), which explicitly treats dynamical fluctuations of the Sm $4f$ shell. We find that SmCo$_5$ exhibits pronounced Sm$^{2+}$--Sm$^{3+}$ valence fluctuations, with the $4f$ ground state dominated by $f^5$ and $f^6$ configurations. The resulting dynamical $4f$ correlations yield near compensation of the Sm spin and orbital moments and provide a quantitative description of the electronic structure, magnetic moments, and large uniaxial magnetic anisotropy of SmCo$_5$. Upon replacing Co with Cu, the balance shifts toward the $f^6$ configuration, with substantial changes in the Sm spin and orbital moments. In SmCu$_5$, this evolution of the $4f$ configuration is accompanied by a pronounced reduction of both the total magnetic moment and magnetic anisotropy. These results demonstrate that dynamical $4f$ valence fluctuations are essential for understanding the contrasting magnetic properties of SmCo$_5$ and SmCu$_5$ and provide a microscopic framework for describing magnetic anisotropy upon Co to Cu substitution in Sm(Co,Cu)$_5$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.06568",
  "author_total": 8,
  "authors": [
    {
      "name": "Alexander B. Shick"
    },
    {
      "name": "Alexander V. Andreev"
    },
    {
      "name": "Evgenia A. Tereshina-Chitrova"
    },
    {
      "name": "Institute of Physics"
    },
    {
      "name": "the Czech Academy of Sciences"
    },
    {
      "name": "Na Slovance 2"
    },
    {
      "name": "CZ-18221 Prague"
    },
    {
      "name": "Czech Republic"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2x6b46jxg6z00.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.06568",
  "fulltext_url": null,
  "id": "2x6b46jxg6z00",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.06568",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "arxiv",
      "cond-mat.str-el"
    ],
    [
      "openalex",
      "3104|Rare-earth and actinide compounds"
    ]
  ],
  "openalex": "W7220677418",
  "pdf_url": "https://arxiv.org/pdf/2610.06568",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2x6b46jxg6z00.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2610.06568",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.06568"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Dynamical Valence Fluctuations and Magnetic Anisotropy in Sm(Co,Cu)$_5$",
  "title_text": "Dynamical Valence Fluctuations and Magnetic Anisotropy in Sm(Co,Cu)_5",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/2x6b46jxg6z00",
  "venue": "arXiv",
  "versions": []
}