物理工学コースからのおしらせ

物理工学ユニットでは、以下のように談話会を開催します。

講師：Dr. Ulf Wiedwald　（Faculty of Physics and Center for Nanointegration, University of Duisburg-Essen, Germany）

演題：Magnetite-Gold and Ferrite Nanoparticles: From Physics to Theranostics

日時：12月3日（火）13：30～

場所：理学棟４０４リフレッシュルーム

The application of magnetic nanoparticles (MNPs) in biomedicine is one of the most dynamic and promising fields of nanoparticles research. Two examples for the use of multifunctional MNPs in theranostics are agents in magnetic resonance imaging (MRI) and magnetic particle hyperthermia (MPH) for the localized treatment of cancer. We designed, synthesized and tested various MNPs like ferrites, core-shell architectures, and magnetite-gold (Fe₃O₄-Au) hybrids for optimized properties. Here, we present pairwise connected Fe₃O₄-Au hybrids with diameters of 6-44 nm Fe₃O₄ and 3-11 nm Au aiming for optimized theranostics response. Figure 1 shows high-resolution transmission electron microscopy (HRTEM) images and corresponding FFT images of 15 nm and 25 nm Fe₃O₄-Au hybrids. The shape of such hybrid MNPs can be tuned from spherical to octahedral motifs depending on the reaction temperature and time. With increasing MNPs diameter from 6 to 25 nm in agarose mimicking tissues, the MPH reveal that the specific loss power increases from 12 to 327 W・g_Fe^-1, while for the MRI, we observe the growth of the r₂-relaxivity from 118 to 612 mM^-1s^-1. The 25 nm and 44 nm diameter MNPs show similar theranostic performances. These values are significantly enhanced in comparison to other Fe₃O₄-Au hybrids due to their octahedral shape and large saturation magnetization. As a practical application, MRI-controlled drug delivery and dual-mode MRI/fluorescent imaging are presented for the optimized MNPs size of 25 nm.

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世話人：一柳　優子

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講師：Rafael Costa-Amaral and Yoshihiro Gohda
　　　(Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan)

演題：Using DFT to Investigate the Magnetoelectric Coupling at Fe₃Si/Tm/BaTiO₃ (001) (TM = Sc to Cd) Interfaces

日時：12月3日（火）16：15～

場所：総合研究棟W701

The coupling of magnetic and ferroelectric properties at interfaces between ferromagnetic and ferroelectric materials has been studied due to the possibility of manipulate magnetic states by using lower energy-demanding electric field rather than its magnetic counterpart [1], which opens the possibility to reduce energy consumption in spintronics. Hence, we investigate by means of Density Functional Theory the magnetoelectric coupling (MEC) at the interface of multiferroic systems composed by 3d and 4d transition-metal (TM) monolayers sandwiched between Fe₃Si (001) and BaTiO₃ (001), which are the ferromagnetic and ferroelectric phases, respectively. We report the values of their MEC coefficients and compare with similar multiferroic systems in literature [2]. We also present analysis of electronic properties that help us understand the mechanisms that drive the interfacial MEC.

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世話人：レービガー　ハンネス

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