How shape and internal structure affect the magnetic properties of anisometric magnetite nanoparticles

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• 作者：Helena Gavilá ; n^a ; ^{helena_gr@icmm.csic.es} ; Oliver Posth^b ; Lara K. Bogart^c ; Uwe Steinhoff^b ; Lucí ; a Gutié ; rrez^a ; ^d ; ; M. Puerto Morales^a
• 关键词：Nanoparticles ; Magnetic properties ; Size effects ; Shape dependence ; Structure properties relationship
• 刊名：Acta Materialia
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：125
• 期：Complete
• 页码：416-424
• 全文大小：2160 K
• 卷排序：125

文摘

A three-step aqueous approach to obtain large (>50 nm) magnetite single-core particles has been developed. The steps are a) synthesis of antiferromagnetic nanoparticles, b) particle coating and c) subsequent reduction of the core material to magnetite. By variation of precursor material and process conditions, the synthesis yielded rhombohedra, discs or needles below 200 nm. A combination of X-ray diffraction, 57Fe Mössbauer spectroscopy and infrared spectroscopy confirmed magnetite to be the dominant final core material. From transmission electron microscopy, we identified porous structures after the reduction. Magnetic characterization of the different magnetic nanopaticles revealed strikingly different magnetic behaviour depending on their shape, internal structure and reduction process. We conclude that each of these parameters have to be considered in further characterization of large magnetite nanoparticles.