Magnetic Domain State and Anisotropy in Hematite (α-Fe2O3) From First-Order Reversal Curve Diagrams

Andrew P. Roberts*, Xiang Zhao, Pengxiang Hu, Alexandra Abrajevitch, Yen Hua Chen, Richard J. Harrison, David Heslop, Zhaoxia Jiang, Jinhua Li, Qingsong Liu, Adrian R. Muxworthy, Hirokuni Oda, Hugh St C. O’Neill, Brad J. Pillans, Tetsuro Sato

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Hematite carries magnetic signals of interest in tectonic, paleoclimatic, paleomagnetic, and planetary studies. First-order reversal curve (FORC) diagrams have become an important tool for assessing the domain state of, and magnetostatic interactions among, magnetic particles in such studies. We present here FORC diagrams for diverse hematite samples, which provide a catalog for comparison with other studies and explain key features observed for hematite. Ridge-type signatures typical of uniaxial single-domain particle assemblages and “kidney-shaped” FORC signatures, and combinations of these responses, occur commonly in natural and synthetic hematite. Asymmetric features that arise from the triaxial basal plane anisotropy of hematite contribute to vertical spreading in kidney-shaped FORC distributions and are intrinsic responses even for magnetostatically noninteracting particles. The dominant FORC distribution type in a sample (ridge, kidney-shaped, or mixture) depends on the balance between uniaxial/triaxial switching. The identified signals explain magnetization switching and anisotropy features that are intrinsic to the magnetic properties of hematite and other materials with multiaxial magnetic anisotropy.

Original languageEnglish
Article numbere2021JB023027
JournalJournal of Geophysical Research: Solid Earth
Volume126
Issue number12
DOIs
Publication statusPublished - 2021 Dec
Externally publishedYes

Keywords

  • FORC
  • anisotropy
  • domain state
  • hematite
  • multiaxial
  • uniaxial

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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