TY - JOUR

T1 - Theoretical grain size limits for single-domain, pseudo-single-domain and multi-domain behavior in titanomagnetite (x = 0.6) as a function of low-temperature oxidation

AU - Moskowitz, Bruce M

PY - 1980/4

Y1 - 1980/4

N2 - A theoretical model of grain size variation of domain transitions in titanomagnetite (x = 0.6) as a function of oxidation (z) is presented. The superparamagnetic (SP) to single-domain (SD) transition ds, the SD to two-domain (TD) transition d0, the TD to three-domain (3D) transition and the pseudo-single domain (PSD) to multi-domain (MD) transition are calculated as a function of z. It is shown that all the transition grain sizes increase with z, except for the PSD-MD transition for z > 0.6. The calculations predict that ds increases from 0.044 to 0.197 μm, d0 increases from 0.54 to 13 μm, the TD-3D transition increases from 1.6 to 49 μm as z varies from 0 to 0.8. The PSD-MD transition increases from 42 μm at z = 0 to 150 μm at z = 0.6, whereas between z = 0.6 to z = 0.8, the PSD-MD transition decreases to 49 μm. Qualitatively, the model explains some of the trends in magnetic properties of submarine basalts with low-temperature oxidation. Quantitatively, the model does give reasonable estimates of the PSD-MD boundary and d0, which are close to the experimental values for x = 0.6 and z = 0. Furthermore, the model predicts that psarks or two-domain grains could be the major contributors to the remanence of oxidized submarine pillow basalts.

AB - A theoretical model of grain size variation of domain transitions in titanomagnetite (x = 0.6) as a function of oxidation (z) is presented. The superparamagnetic (SP) to single-domain (SD) transition ds, the SD to two-domain (TD) transition d0, the TD to three-domain (3D) transition and the pseudo-single domain (PSD) to multi-domain (MD) transition are calculated as a function of z. It is shown that all the transition grain sizes increase with z, except for the PSD-MD transition for z > 0.6. The calculations predict that ds increases from 0.044 to 0.197 μm, d0 increases from 0.54 to 13 μm, the TD-3D transition increases from 1.6 to 49 μm as z varies from 0 to 0.8. The PSD-MD transition increases from 42 μm at z = 0 to 150 μm at z = 0.6, whereas between z = 0.6 to z = 0.8, the PSD-MD transition decreases to 49 μm. Qualitatively, the model explains some of the trends in magnetic properties of submarine basalts with low-temperature oxidation. Quantitatively, the model does give reasonable estimates of the PSD-MD boundary and d0, which are close to the experimental values for x = 0.6 and z = 0. Furthermore, the model predicts that psarks or two-domain grains could be the major contributors to the remanence of oxidized submarine pillow basalts.

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U2 - 10.1016/0012-821X(80)90045-X

DO - 10.1016/0012-821X(80)90045-X

M3 - Article

AN - SCOPUS:0018912721

VL - 47

SP - 285

EP - 293

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

IS - 2

ER -