Magneto-Optical Properties and Size Effect of Ferromagnetic Metal Nanoparticles
Magneto-Optical Properties and Size Effect of Ferromagnetic Metal Nanoparticles
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DOI：
10.7567/jjap.52.073003
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发表时间：
2013-07
影响因子：
1.5
通讯作者：
T. Kaihara;M. Mizuguchi;K. Takanashi;H. Shimizu
中科院分区：
文献类型：
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作者：
T. Kaihara;M. Mizuguchi;K. Takanashi;H. Shimizu
研究了局部表面等离子体共振（LSPR）对铁磁性金属（Fe和Co）纳米粒子的磁光效应。基于Mie散射理论估计了LSPR对铁磁性金属纳米粒子的电场增强，并与金纳米粒子进行了比较。铁磁性金属纳米粒子的电场增强为15 ~ 17，是Au纳米粒子的一半。为了解释计算结果，我们采用自组装工艺制备了铁磁性金属纳米颗粒。我们测量了铁磁纳米粒子的透射光谱和法拉第效应。虽然没有观察到明显的MO增强，但在厚度小于6 nm的样品中，我们发现了特征MO光谱和波长大于800 nm的峰移。我们对尺寸效应进行了数值研究，并重现了实验结果。结果表明，铁磁金属纳米粒子的局部等离子体激元可以产生电场增强，但这种增强不足以增加MO效应，并且纳米铁磁金属的MO效应可能受尺寸效应的影响而不是LSPR的影响。
We investigated the magneto-optical (MO) effect with localized surface plasmon resonance (LSPR) on ferromagnetic metal (Fe and Co) nanoparticles. We estimated the electric-field enhancement of the ferromagnetic metal nanoparticles caused by LSPR based on Mie scattering theory and compared it with that of Au nanoparticles. The electric-field enhancement of the ferromagnetic metal nanoparticles was 15–17, which is half of that of the Au nanoparticles. In order to explain the calculated results, we prepared ferromagnetic metal nanoparticles by a self-assembly process. We measured the optical transmission spectra and Faraday effect of the ferromagnetic nanoparticles. Although remarkable MO enhancement was not observed, we found characteristic MO spectra and a peak shift at wavelengths longer than 800 nm in samples whose thickness was less than 6 nm. We numerically investigated the size effect and reproduced the experimental results. We concluded that localized plasmons of ferromagnetic metal nanoparticles can produce electric-field enhancement, but the enhancement is not enough to increase the MO effect, and that the MO effect of nanosized ferromagnetic metals could be influenced by size effects rather than by LSPR.