Examination of magnetite nanoparticles utilising the temperature dependent magnetorelaxometry

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• 作者：M. Bü ; ttner^a ; ^{Markus.Buettner@uni-jena.de} ; P. Weber^a ; C. Lang^b ; M. Rö ; der^c ; D. Schü ; ler^b ; P. Gö ; rnert^c ; P. Seidel^a
• 关键词：Magnetite nanoparticle ; Temperature dependent magnetorelaxation measurement ; Né ; el relaxation ; Low temperature coercivity measurement ; Magnetosome ; Verwey transition ; Spin glass ; Memory effect ; Magnetic nanoparticle
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2011
• 出版时间：May 2011
• 年：2011
• 卷：323
• 期：9
• 页码：1179-1184
• 全文大小：356 K

文摘

We investigated the magnetic properties of two kinds of magnetosomes (25–42 nm) produced by the magneto-tactic bacterium Magnetospirillum gryphiswaldense. At temperatures between 4.2 K and room temperature the temperature dependent magnetorelaxation (TMRX) method was used. We found three areas with magnetic signals and discuss them in this paper using the results of additional hysteresis loop measurements. The signals detected above 300 K show the lower end of a beginning energy barrier distribution. The signals between 70 and 120 K lie in the area of the Verwey transition and disappear over time due to aging processes. In addition to these signals, other signals at temperatures between 4.2 and 70 K were found and possible causes are discussed.