Rapid Faraday Rotation on ε-Iron Oxide Magnetic Nanoparticles by Visible and Terahertz Pulsed Light.
Shin-Ichi OhkoshiKenta ImotoAsuka NamaiMarie YoshikiyoSeiji MiyashitaHongsong QiuShodai KimotoKosaku KatoMakoto NakajimaPublished in: Journal of the American Chemical Society (2019)
Light- or electromagnetic wave-responsive magnetism is an attractive issue in spin chemistry and optical materials science. Herein we show the magnetization reversal induced by visible-light pulsed laser and the ultrafast dynamic magnetooptical effect caused by terahertz (THz) pulsed laser irradiation onto chemically synthesized magnetic films based on gallium-titanium-cobalt-substituted ε-Fe2O3 (GTC-ε-Fe2O3) and ε-Fe2O3 nanoparticles. Visible-light pulsed laser irradiation switches the sign of the Faraday effect in GTC-ε-Fe2O3 films. On the other hand, irradiating the ε-Fe2O3 film with pulsed THz light induces an ultrafast Faraday rotation in an extremely short time of 400 fs. The time evolution dynamics of these ultrafast magnetooptical effects are theoretically demonstrated by stochastic Landau-Lifshitz-Gilbert calculations of a nanoparticle model that considers all motions of the individual spins. These ε-iron oxide magnetic nanomaterials are expected to contribute to high-density magnetic memory media or high-speed operation circuit magnetic devices.
Keyphrases
- high speed
- iron oxide
- visible light
- molecularly imprinted
- atomic force microscopy
- room temperature
- high density
- magnetic nanoparticles
- high resolution
- public health
- density functional theory
- energy transfer
- molecular dynamics
- working memory
- cancer therapy
- molecular dynamics simulations
- high frequency
- radiation induced
- ionic liquid