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Compositional control of anisotropy of remanent and induced magnetization in synthetic samples
Author(s) -
Johns Mary,
Jackson Mike
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl01418
Subject(s) - remanence , anisotropy , magnetite , paramagnetism , magnetic anisotropy , magnetic susceptibility , chlorite , condensed matter physics , materials science , isotropy , ferrimagnetism , magnetization , rock magnetism , magnetocrystalline anisotropy , nuclear magnetic resonance , geology , magnetic field , mineralogy , composite material , physics , optics , metallurgy , quartz , quantum mechanics
Anisotropy of remanent and induced magnetization was found to be compositionally controlled in synthetic samples of varying proportions of chlorite (a platy paramagnet), manganese oxide (an isotropic paramagnet), and magnetite (an anisotropic ferrimagnet). Grains were magnetically aligned in a 100 mT field, then uniaxially compressed at 27.6 MPa to produce an L‐S fabric. Anisotropy of anhysteretic susceptibility (AAS) and anisotropy of magnetic low‐field susceptibility (AMS) are coaxial, and anhysteretic susceptibility is consistently more anisotropic than low‐field susceptibility. AMS increases with the addition of oblate magnetite, but decreases with addition of isotropic Mn 2 O 3 to chlorite. These experiments demonstrate that magnetic anisotropy depends on the shape, relative magnetic intensity, and proportion of the magnetic minerals.