کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10709570 | 1024512 | 2012 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxidized magnetosomes in magnetotactic bacteria
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Single domain magnetite particles formed in chain assemblies by magnetotactic bacteria (MTB) are taken as proxy in inferring environmental and Earth's magnetism. The reliable use of magnetosomes in MTB, or their fossil remains (magnetofossils), requires that they are unaffected by oxidation. Here we present experimental data from saturation isothermal remanent magnetization (SIRM) and ferromagnetic resonance spectroscopy (FMR) between room temperature and 10Â K, which were applied to detect oxidation in intact MTB. The distinction of non-oxidized from oxidized MTB-assemblies is based mainly on two different characteristic physical properties: (i) the intrinsic Verwey transition in pure magnetite, and (ii) blocking of spins of nano-sized products formed during oxidation at the surface or the interior of the magnetosomes. Suppression of the Verwey transition due to oxidation prevents the shift of the anisotropy axes, which in turn conserves the anisotropic properties at room temperature down to low temperature. The presented methodology assures a distinction between non- and oxidized magnetite assemblies, with pronounced certainty, unlike standard dc methods.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 324, Issue 7, April 2012, Pages 1281-1284
Journal: Journal of Magnetism and Magnetic Materials - Volume 324, Issue 7, April 2012, Pages 1281-1284
نویسندگان
Andreas U. Gehring, Michalis Charilaou, Inés GarcÃa-Rubio,