Preparation of Ni Nanoparticles on Submicron-Sized Al2O3 Powdery Substrate by Polyhedral-Barrel-Sputtering Technique and Their Magnetic Properties
Preparation of Ni Nanoparticles on Submicron-Sized Al2O3 Powdery Substrate by Polyhedral-Barrel-Sputtering Technique and Their Magnetic Properties
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DOI：
10.1143/jjap.51.065201
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发表时间：
2012-05
影响因子：
1.5
通讯作者：
S. Akamaru;M. Inoue;Yuji Honda;A. Taguchi;T. Abe
中科院分区：
文献类型：
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作者：
S. Akamaru;M. Inoue;Yuji Honda;A. Taguchi;T. Abe
采用多面体桶溅射技术在亚微米级 Al2O3 粉末基底上制备了 Ni 纳米粒子，并研究了其微观结构和磁性能。通过该技术，在 Al2O3 颗粒表面制备了平均直径为 3.9–7.9 nm 的纳米颗粒，并使用对数正态公式重现了纳米颗粒的尺寸分布。沉积的镍纳米粒子由空气氧化形成的氧化镍层和镍核组成。磁化曲线表明所有制备的样品都表现出超顺磁行为，这可以通过考虑镍纳米颗粒的尺寸分布来解释。还观察到由核壳结构引起的交换偏倚效应。根据镍芯的饱和磁矩，估计表面层的厚度为1.0-1.3 nm，与块体镍的钝化氧化层相当。
Ni nanoparticles were prepared on a submicron-sized Al2O3 powdery substrate by the polyhedral-barrel-sputtering technique and their microstructure and magnetic properties were investigated. By this technique, nanoparticles with an average diameter of 3.9–7.9 nm were prepared on the Al2O3 particles surface, and the size distribution of the nanoparticles was reproduced using a log-normal formula. The deposited Ni nanoparticles were composed of a NiO layer, which was formed by air oxidation, and a Ni core. The magnetization curves suggested that the all the prepared samples exhibited superparamagnetic behavior, which can be explained by considering the size distribution of the Ni nanoparticles. An exchange-bias effect, which arising from the core–shell structure, was also observed. From the saturated magnetic moments of the Ni core, the thickness of the surface layer was estimated to be 1.0–1.3 nm, which was comparable with that of passivated oxide layer of bulk Ni.