Magnetically superior and easy to handle L10-FePt nanocrystals -: art. no. 032503
Magnetically superior and easy to handle L10-FePt nanocrystals -: art. no. 032503
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DOI：
10.1063/1.1995959
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发表时间：
2005-07-18
影响因子：
4
通讯作者：
Takano, M
中科院分区：
文献类型：
--
作者：
Yamamoto, S;Morimoto, Y;Takano, M
我们报道了单分散L1（0）-FePt纳米晶的合成，其不仅具有上级磁性，而且通过可分散在溶剂中而易于处理。由于SiO2涂层较厚，即使在900 ℃下也可以进行形成L1（0）结构所需的热处理，而不会导致聚结和粗化。然后以特定的方式除去保护壳，使我们能够在水分散体中回收L1（0）-FePt纳米晶体。SiO2-包覆的纳米晶体在室温下显示出18.5 kOe的高磁化率，尽管它们的核尺寸仅为6.5 nm的直径，和水分散的纳米晶体，这是在外场下冻结的磁滞回线，几乎是矩形的，这表明它们的磁性和结构取向可以实现。(c)2005年美国物理学会。
We report synthesis of monodisperse L1(0)-FePt nanocrystals that are not only superior in magnetism but also easy to handle through being dispersible in solvents. Thanks to a thick SiO2 coating, the thermal treatment needed to form the L1(0) structure can be done even at 900 degrees C without inducing coalescence and coarsening. The protecting shell was thereafter removed in a specific way that enabled us to recover the L1(0)-FePt nanocrystals in a water dispersion. The SiO2-coated nanocrystals show a high coercivity of 18.5 kOe at room temperature in spite of their core size of only 6.5 nm in diameter, and the hysteresis loop of the water-dispersed nanocrystals, which were frozen under an external field, was almost rectangular indicating that their magnetic and structural orientation could be attained. (c) 2005 American Institute of Physics.