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Resolving the Origin of Pseudo‐Single Domain Magnetic Behavior
Author(s) -
Roberts Andrew P.,
Almeida Trevor P.,
Church Nathan S.,
Harrison Richard J.,
Heslop David,
Li Yiliang,
Li Jinhua,
Muxworthy Adrian R.,
Williams Wyn,
Zhao Xiang
Publication year - 2017
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2017jb014860
Subject(s) - nucleation , condensed matter physics , magnetism , vortex , magnetite , single domain , vortex state , paleomagnetism , physics , range (aeronautics) , rock magnetism , magnetic domain , magnetization , geology , materials science , geophysics , magnetic field , superconductivity , remanence , quantum mechanics , mechanics , thermodynamics , paleontology , composite material
The term “pseudo‐single domain” (PSD) has been used to describe the transitional state in rock magnetism that spans the particle size range between the single domain (SD) and multidomain (MD) states. The particle size range for the stable SD state in the most commonly occurring terrestrial magnetic mineral, magnetite, is so narrow (~20–75 nm) that it is widely considered that much of the paleomagnetic record of interest is carried by PSD rather than stable SD particles. The PSD concept has, thus, become the dominant explanation for the magnetization associated with a major fraction of particles that record paleomagnetic signals throughout geological time. In this paper, we argue that in contrast to the SD and MD states, the term PSD does not describe the relevant physical processes, which have been documented extensively using three‐dimensional micromagnetic modeling and by parallel research in material science and solid‐state physics. We also argue that features attributed to PSD behavior can be explained by nucleation of a single magnetic vortex immediately above the maximum stable SD transition size. With increasing particle size, multiple vortices, antivortices, and domain walls can nucleate, which produce variable cancellation of magnetic moments and a gradual transition into the MD state. Thus, while the term PSD describes a well‐known transitional state, it fails to describe adequately the physics of the relevant processes. We recommend that use of this term should be discontinued in favor of “vortex state,” which spans a range of behaviors associated with magnetic vortices.