The effect of surface spin disorder on the magnetism of γ-Fe2O3 nanoparticle dispersions
The effect of surface spin disorder on the magnetism of γ-Fe2O3 nanoparticle dispersions
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DOI：
10.1088/0957-4484/18/45/455704
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发表时间：
2007-11-14
期刊：
影响因子：
3.5
通讯作者：
van Lierop, J.
中科院分区：
文献类型：
--
作者：
Shendruk, T. N.;Desautels, R. D.;van Lierop, J.
由于表面有大量的自旋无序，单分散的7 nmγ-Fe2O3纳米颗粒的纳米磁性表现出独特的特征。为了正确地描述稀散射的超顺磁性，需要考虑磁各向异性和围绕有序核的无序自旋的壳层的影响。纳米颗粒壳层的无序自旋结构与有序核的自旋结构交换耦合。当纳米颗粒分散体被场冷却时，这实现了交换偏置环路移动，十六进制。表面自旋无序还导致纳米粒子的总饱和磁化强度随着温度的升高而异常地呈指数式下降。
The nanomagnetism of monodisperse 7 nm gamma-Fe2O3 nanoparticles exhibits unique features due to a significant amount of surface spin disorder. To correctly characterize the superparamagnetism of a dilute dispersion requires including the effects of the magnetic anisotropy and a shell of disordered spins surrounding the ordered core. The nanoparticle shell's disordered spin structure is exchange coupled to that of the ordered core. This enables an exchange bias loop shift, Hex, when the nanoparticle dispersion is field cooled. The surface spin disorder also leads to an unusual exponential-like decrease of the nanoparticle's total saturation magnetization with increasing temperature.