磁気光学デバイスに用いるBi-YIG/Au複合微粒子の作製

抄録

Although immunochromatograph using nanoparticles has some merits such as an ease of use and a quick response, it has some issues such as a poor sensitivity and a lack of quantitativity. To overcome the issues, we investigate a new immunoassay method using a magneto-optical (MO) effect based on nanoparticle technologies. Bismuth-substituted yttrium-iron garnet (Bi-YIG) is one of the candidates, which exhibits a large Faraday effect. To enhance the Faraday effect for highly sensitive MO immunoassay, surface plasmon resonance (SPR) effect is employed in the preset study. Au nanoparticles have an absorption peak based on the SPR effect in the wavelength range of 500-600 nm by optimizing their size and interparticle distance. We fabricate MO and plasmonic particles composed of a Bi-YIG particle as a core and Au nanoparticles deposited on the core. The clear SPR absorption and the MO enhancement are obtained in the composites with a larger amount of Au nanoparticles deposited on Bi-YIG particles. The enhancement of the Faraday rotation is observed in the range of 500-700 nm, corresponding to the wavelength range where the clear SPR absorption was observed. The Faraday rotation increases by 50% in maximum at around 550 nm of wavelength.