Preparation of ultrafine FePt nanoparticles by chemical reduction in PAMAM-OH template

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• 作者：Litao Bai ; Haiying Wan ; Shane C. Street
• 关键词：FePt nanoparticles ; Dendrimer ; Magnetic Properties
• 刊名：Colloids and Surfaces A: Physicochemical and Engineering Aspects
• 出版年：2009
• 出版时间：5 October 2009
• 年：2009
• 卷：349
• 期：1-3
• 页码：23-28
• 全文大小：1173 K

文摘

Using dendrimer templates, FePt nanoparticles with narrow size-distribution were prepared by a simple chemical reduction method at room temperature. In this approach, PAMAM-OH dendrimers act as templates in which metal ions are coordinated in, and NaBH₄ acts as reductant. The FePt nanoparticles were synthesized in aqueous solution. The as-made FePt nanoparticles are spherical with an average size of 3 nm and have the chemically disordered face-center-cubic (fcc) structure. The FePt nanoparticles can be transformed to the face-center-tetragonal (fct) phase after annealing at 700 °C for 1 h. The as-prepared fcc FePt nanoparticles are found to be superparamagnetic at room temperature. After annealing in a reducing atmosphere, the FePt nanoparticles transform to ferromagnetic and show high covercivity. The structural and magnetic properties of the as-made and annealed FePt nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and alternating gradient magnetometry (AGM).