Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, P. R. China.
Nanoscale. 2018 May 31;10(21):10123-10129. doi: 10.1039/c8nr01393d.
Discovering how the magnetization reversal process is governed by the magnetic anisotropy in magnetic nanomaterials is essential and significant to understand the magnetic behaviour of micro-magnetics and to facilitate the design of magnetic nanostructures for diverse technological applications. In this study, we present a direct observation of a dynamical magnetization reversal process in single NiFe2O4 nanowire, thus clearly revealing the domination of shape anisotropy on its magnetic behaviour. Individual nanoparticles on the NiFe2O4 nanowire appear as single domain states in the remanence state, which is maintained until the magnetic field reaches 200 Oe. The magnetization reversal mechanism of the nanowire is observed to be a curling rotation mode. These observations are further verified by micromagnetic computational simulations. Our findings show that the modulation of shape anisotropy is an efficient way to tune the magnetic behaviours of cubic spinel nano-ferrites.
发现磁性各向异性如何控制磁性纳米材料中的磁化反转过程，对于理解微磁体的磁性行为以及为各种技术应用设计磁性纳米结构至关重要。在这项研究中，我们直接观察了单根 NiFe2O4 纳米线中的动态磁化反转过程，从而清楚地揭示了形状各向异性对其磁性行为的控制。在剩磁状态下，NiFe2O4 纳米线上的单个纳米颗粒表现为单畴状态，这种状态一直持续到磁场达到 200 Oe。观察到纳米线的磁化反转机制是一种卷曲旋转模式。这些观察结果通过微磁计算模拟得到了进一步验证。我们的发现表明，调制形状各向异性是一种有效方法，可以调整立方尖晶石纳米铁氧体的磁性行为。
