Shape control and associated magnetic properties of spinel cobalt ferrite nanocrystals
Shape control and associated magnetic properties of spinel cobalt ferrite nanocrystals
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DOI：
10.1021/ja049931r
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发表时间：
2004-05-19
影响因子：
15
通讯作者：
Zhang, ZJ
中科院分区：
文献类型：
--
作者：
Song, Q;Zhang, ZJ
通过结合非水解反应和种子介导生长，可以合成高质量和单分散的尖晶石型钴铁氧体CoFe2O4纳米晶，其具有高度可控的近球形或几乎完美的立方体形状。通过控制纳米晶的生长速率，纳米晶的形状也可以在球形和立方形貌之间可逆地互换。此外，磁性研究表明，无论是球形还是立方体形状，纳米晶体的阻断温度、饱和磁化强度和剩磁都仅由尺寸决定。然而，由于表面各向异性的影响，纳米晶体的形状是纳米晶体导电性的主要因素。这种具有不同形状的磁性纳米晶体在磁性的基础理解和磁性纳米晶体用于高密度信息存储的技术应用方面具有巨大的潜力。
By combining nonhydrolytic reaction with seed-mediated growth, high-quality and monodisperse spinel cobalt ferrite, CoFe2O4, nanocrystals can be synthesized with a highly controllable shape of nearly spherical or almost perfectly cubic. The shape of the nanocrystals can also be reversibly interchanged between spherical and cubic morphology through controlling nanocrystal growth rate. Furthermore, the magnetic studies show that the blocking temperature, saturation, and remanent magnetization of nanocrystals are solely determined by the size regardless the spherical or cubic shape. However, the shape of the nanocrystals is a dominating factor for the coercivity of nanocrystals due to the effect of surface anisotropy. Such magnetic nanocrystals with distinct shapes possess tremendous potentials in fundamental understanding of magnetism and in technological applications of magnetic nanocrystals for high-density information storage.