Flipping anisotropy and changing magnetization reversal modes in nano-confined Cobalt structures
Flipping anisotropy and changing magnetization reversal modes in nano-confined Cobalt structures
复制标题
纳米限制钴结构中翻转各向异性和改变磁化反转模式
DOI：
10.1016/j.jmmm.2018.12.093
复制
发表时间：
2019
影响因子：
2.7
通讯作者：
S. Banerjee
中科院分区：
文献类型：
--
作者：
K. Nath;J. Sinha;S. Banerjee
我们研究了通过在两个单独的纳米多孔阳极氧化铝 (AAO) 模板上溅射 Co 创建的钴纳米线阵列的温度依赖性磁性，每个模板的孔径分别为 50 nm 和 10 nm。我们观察到两个纳米线阵列的易磁化轴的差异以及低温下易磁化轴的翻转。发现室温下50nm纳米线阵列的易轴垂直于纳米线长轴，而对于10nm阵列，易轴平行于线轴。然而，随着温度的降低，两个阵列的易轴都偏离了室温下的方向。与此同时，饱和磁场和矫顽场的值在低温下突然增加，并伴随着饱和磁场的交叉。我们提出，随着温度的降低，由于氧化铝模板在纳米线阵列中产生应力，纳米线中存在的钴的磁晶各向异性会发生变化。我们通过微磁模拟生成 M(H) 曲线来支持我们的实验结果，并研究具有不同各向异性的纳米线阵列中的磁化反转过程。随着各向异性的降低（我们认为这是由低温应力引发的），我们的模拟显示出源自纳米线的磁涡流状不稳定性。我们通过模拟提出了可能的畴反转模式：50nm 纳米线中的卷曲以及 10nm 纳米线中的相干旋转或屈曲。我们的结果表明，温度可以作为调节 AAO 中嵌入的 Co 纳米线的磁各向异性并产生不寻常的磁性纹理的有效工具。
We investigate the temperature dependent magnetic properties of arrays of Cobalt nanowires created by sputtering Co on two separate nanoporous anodized alumina (AAO) templates each with pores of diameter 50 nm and 10 nm. We observe differences in the easy axis of magnetization for the two nanowire arrays and a flip in the easy axis at low temperatures. The easy axis of 50 nm nanowire array at room temperature is found to be perpendicular to the nanowire long axis, whereas for 10 nm arrays the easy axis is parallel to the wire axis. With lowering of temperature, however the easy axes of both arrays orient away from that at room temperature. Along with that the saturation magnetic field and coercive field show sudden increase in their values at low temperatures, accompanied by a crossing over seen in the saturation magnetic fields. We propose changes in magneto-crystalline anisotropy of cobalt present in the nanowires as a result of the stress developed in the nanowire array due to the alumina template, with lowering of temperature. We support our experimental results with micro-magnetic simulations done to generate theM(H) curves and study the magnetization reversal processes in the nanowire arrays with varying anisotropies. With lowering of anisotropy which we believe is triggered by stress at low temperature, our simulations show magnetic vortex like instabilities originating in the nanowires. We suggest the possible modes of domain reversals: curling in 50 nm and either coherent rotation or buckling in 10 nm nanowires through our simulations. Our results suggest that temperature can serve as an effective tool to tune magnetic anisotropy in Co nanowires embedded in AAO and generate unusual magnetic textures.
影响因子：
56.9
作者：
MASUDA, H;FUKUDA, K
通讯作者：
FUKUDA, K