Titlebar

Export bibliographic data
Literature by the same author
plus on the publication server
plus at Google Scholar

 

Experimental mixtures of superparamagnetic and single domain magnetite with respect to Day-Dunlop plots

Title data

Kumari, Monika ; Hirt, Ann M. ; Uebe, René ; Schüler, Dirk ; Tompa, Éva ; Pósfai, Mihály ; Lorenz, Wolfram ; Ahrentorp, Fredrik ; Jonasson, Christian ; Johansson, Christer:
Experimental mixtures of superparamagnetic and single domain magnetite with respect to Day-Dunlop plots.
In: Geochemistry, Geophysics, Geosystems. Vol. 16 (12 June 2015) Issue 6 . - pp. 1739-1752.
ISSN 1525-2027
DOI: https://doi.org/10.1002/2015GC005744

Official URL: Volltext

Abstract in another language

Day-Dunlop plots are widely used in paleomagnetic and environmental studies as a tool to determine the magnetic domain state of magnetite, i.e., superparamagnetic (SP), stable single-domain (SD), pseudosingle-domain (PSD), multidomain (MD), and their mixtures. The few experimental studies that have examined hysteresis properties of SD-SP mixtures of magnetite found that the ratios of saturation remanent magnetization to saturation magnetization and the coercivity of remanence to coercivity are low, when compared to expected theoretical mixing trends based on Langevin theory. This study reexamines Day-Dunlop plots using experimentally controlled mixtures of SD and SP magnetite grains. End-members include magnetotactic bacteria (MSR-1) as the SD source, and a commercial ferrofluid or magnetotactic bacteria (ΔA12) as the SP source. Each SP-component was added incrementally to a SD sample. Experimental results from these mixing series show that the magnetization and coercivity ratios are lower than the theoretical prediction for bulk SP magnetic size. Although steric repulsion was present between the particles, we cannot rule out interaction in the ferrofluid for higher concentrations. The SP bacteria are noninteracting as the magnetite was enclosed by an organic bilipid membrane. Our results demonstrate that the magnetization and coercivity ratios of SD-SP mixtures can lie in the PSD range, and that an unambiguous interpretation of particle size can only be made with information about the magnetic properties of the end-members.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology > Chair Microbiology > Chair Microbiology - Univ.-Prof. Dr. Dirk Schüler
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology > Chair Microbiology
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 500 Natural sciences
500 Science > 570 Life sciences, biology
Date Deposited: 16 Jul 2015 13:54
Last Modified: 09 Apr 2019 07:32
URI: https://eref.uni-bayreuth.de/id/eprint/16688