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Magnetic domain state and anisotropy in hematite (-Fe2O3) from first-order reversal curve diagrams

Published version
Peer-reviewed

Type

Article

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Authors

Roberts, Andrew 
Zhao, Xiang 
Hu, Pengxiang 
Abrajevitch, Alexandra 
Chen, Yen-Hua 

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.

Description

Keywords

hematite, FORC, domain state, anisotropy, multiaxial, uniaxial

Journal Title

Journal of Geophysical Research. Solid Earth

Conference Name

Journal ISSN

2169-9313
2169-9356

Volume Title

Publisher

American Geophysical Union
Sponsorship
European Research Council (320750)
ERC