Reversible Thermal Hysteresis in Heating-Cooling Cycles of Magnetic Susceptibility: A Fine Particle Effect of Magnetite

Zhang, Qi1,2; Appel, Erwin2

2023-03-28

10.1029/2023GL102932

GEOPHYSICAL RESEARCH LETTERS   Impact Factor & Quartile

0094-8276

1944-8007

Thermomagnetic curves of magnetic susceptibility (kappa) are key to characterizing magnetic properties. We report hump-shaped kappa-T curves of magnetite-bearing basalt during heating-cooling cycles to similar to 340 degrees C, with a large thermal hysteresis and similar starting and ending values, even in multiple repeated cycles, ruling out changes in magnetic mineralogy. Based on FORC diagrams and published results of engineered materials, we propose that thermal hysteresis arises from configurations of magnetic moments in clusters of single-domain particles due to dipolar coupling, with different collective behavior during heating and cooling. This effect modifies the hump-shaped thermal relaxation behavior of the individual nanoparticles. FORC and kappa-T results indicate an increase in effective particle sizes after 700 degrees C-heating. Our results are a warning against premature interpretation of a decreasing trend in kappa-T curves by maghemite inversion. Instead, fine particle behavior should be considered when a hump-shaped kappa-T behavior is detected.

SCI

English

First

National Natural Science Foundation of China[42204082] ; German Research Foundation[AP 34/44-1]

Geology

Geosciences, Multidisciplinary

WOS:000952721400001

AMER GEOPHYSICAL UNION

GEOSCIENCES

Web of Science

1.Southern Univ Sci & Technol, Ctr Marine Magnetism CM2, Dept Ocean Sci & Engn, Shenzhen, Peoples R China
2.Univ Tubingen, Dept Geosci, Tubingen, Germany

Zhang, Qi,Appel, Erwin. Reversible Thermal Hysteresis in Heating-Cooling Cycles of Magnetic Susceptibility: A Fine Particle Effect of Magnetite[J]. GEOPHYSICAL RESEARCH LETTERS,2023,50(6).

Zhang, Qi,&Appel, Erwin.(2023).Reversible Thermal Hysteresis in Heating-Cooling Cycles of Magnetic Susceptibility: A Fine Particle Effect of Magnetite.GEOPHYSICAL RESEARCH LETTERS,50(6).

Zhang, Qi,et al."Reversible Thermal Hysteresis in Heating-Cooling Cycles of Magnetic Susceptibility: A Fine Particle Effect of Magnetite".GEOPHYSICAL RESEARCH LETTERS 50.6(2023).