Effects of surface step and substrate temperature on nanostructure of L10–FePt nanoparticles
Effects of surface step and substrate temperature on nanostructure of L10–FePt nanoparticles
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DOI：
10.1063/1.1541641
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发表时间：
2003-05
影响因子：
3.2
通讯作者：
Kazuhisa Sato;Takenori Kajiwara;M. Fujiyoshi;M. Ishimaru;Y. Hirotsu;T. Shinohara
中科院分区：
文献类型：
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作者：
Kazuhisa Sato;Takenori Kajiwara;M. Fujiyoshi;M. Ishimaru;Y. Hirotsu;T. Shinohara
研究了FePT纳米粒子的颗粒尺寸、颗粒密度及其与硬磁性能的关系随衬底温度和衬底表面形貌的变化。在几何平坦的表面上，当衬底温度低于573K时，可以得到颗粒密度为1012 cm−2的密集分散的FePT纳米粒子，而衬底温度在623~823K之间是获得取向良好、隔离良好的具有大矫直力的L10FePT纳米粒子所必需的。在573K以上制备的孤立粒子在873K时没有大量团聚，这可以归因于铂“种子”粒子的“锚定效应”。在300K的温度下测量了FePT纳米颗粒的矫顽力，颗粒尺寸小于10 nm。在673K温度下，采用表面台阶法在微倾斜的NaC l(001)衬底上可以制备出高密度的Fe/Pt纳米颗粒堆积结构。这些颗粒在<100>晶面上经退火后容易聚合。
The variation of the particle size, particle density, and its relation to the hard magnetic properties of FePt nanoparticles with respect to substrate temperatures and substrate surface morphologies has been investigated. On geometrically flat surfaces, densely dispersed FePt nanoparticles with a particle density of 1012 cm−2 were obtained at a substrate temperature below 573 K, while substrate temperatures between 623 and 823 K are necessary for obtaining well-oriented and well-isolated L10–FePt nanoparticles with large coercivity. Isolated particles fabricated above 573 K did not coalesce largely upon annealing at 873 K, which can be attributed to the “anchoring effect” of Pt “seed” particles. The coercivity of FePt nanoparticles was measured at 300 K damped with decreasing particle sizes below 10 nm. High-density areal packing of Fe/Pt nanoparticles could be fabricated at 673 K on a slightly inclined NaCl(001) substrate with surface steps. These particles coalesced easily upon annealing along the 〈100〉...