The University of Tokyo · 물리·천문학
Shinji Miwa 교수의 연구실은 전자기적 상호작용을 활용한 신소재 및 나노스케일에서의 자기적 성질 제어를 핵심으로 하며, 전기장에 의한 자기이성향 제어(Voltage-Controlled Magnetic Anisotropy, VCMA)와 분자 기반 스핀트로닉스 소자의 원리 탐구를 주요 연구 방향으로 삼고 있습니다. 특히, 펄스 전압에 의한 초고속 자기 제어, C60 기반 나노복합재료에서의 자성 및 자화율 변화, 그리고 편광된 전자 스핀의 분자적 선택성(Chiral-Induced Spin Selectivity, CISS) 현상에 기반한 실온 동작 가능한 분자 스핀소자 개발에 주력하고 있습니다. 이는 초저전력 소비의 미래 스핀트로닉스 기기 구현에 기여할 잠재력을 지닙니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Electric fields at interfaces exhibit useful phenomena, such as switching functions in transistors, through electron accumulations and/or electric dipole inductions. We find one potentially unique situation in a metal-dielectric interface in which the electric field is atomically inhomogeneous because of the strong electrostatic screening effect in metals. Such electric fields enable us to access electric quadrupoles of the electron shell. Here we show, by synchrotron X-ray absorption spectrosco
Abstract Electric-field-induced control of magnetic properties at room temperature has attracted considerable attention owing to its significant potential for facilitating the construction of ultralow-power-consumption electric devices. Voltage-controlled magnetic anisotropy (VCMA) effect in ultrathin ferromagnetic metals has shown that the magnetization of nanomagnets can be controlled by electric fields in extremely short periods (down to 0.1 ns). The VCMA effect in metals can be the ultimate
In this study, voltage-controlled magnetic anisotropy (VCMA) in Fe|MgO tunnel junctions was investigated via the magneto-optical Kerr effect, soft x-ray absorption spectroscopy, and magnetic circular dichroism spectroscopy. The Fe|MgO tunnel junctions showed enhanced perpendicular magnetic anisotropy under external negative voltage, which induced charge depletion at the Fe|MgO interface. Despite the application of voltages of opposite polarity, no trace of chemical reaction such as a redox react
Magnetization, electrical conduction, and magnetoresistance (MR) of ${\mathrm{C}}_{60}\text{\ensuremath{-}}\mathrm{Co}$ nanocomposites, where Co nanoparticles are dispersed in ${\mathrm{C}}_{60}$ molecules, have been investigated over a wide temperature range and Co volume fraction. The ${\mathrm{C}}_{60}\text{\ensuremath{-}}\mathrm{Co}$ nanocomposites exhibit MR when the Co volume fraction is controlled in such a way that the conduction mechanism is dominated by tunneling of carriers between Co
Chirality-induced current-perpendicular-to-plane magnetoresistance (CPP-MR) originates from current-induced spin polarization in molecules. The current-induced spin polarization is widely recognized as a fundamental principle of chiral-induced spin selectivity (CISS). In this study, we investigate chirality-induced current-in-plane magnetoresistance (CIP-MR) in a chiral molecule/ferromagnetic metal bilayer at room temperature. In contrast to CPP-MR, CIP-MR observed in the present study requires
C60–Co nano-composites, in which Co nano-particles are embedded in C60 molecules, have been fabricated and a magnetoresistance (MR) ratio of 8% has been observed at T = 4.2 K. In addition, we have succeeded in observing a clear MR curve even at room temperature (RT). The MR effect is ascribed to magnetization of the Co nano-particles and spin-dependent transport in C60 molecules. This study directly indicates that RT operation of molecular spin devices can be realized.
Spin torque is a promising technique for flipping magnetic orientation in nanomagnets used in low-power computer memories, but accurately measuring this torque is difficult. A new experiment shows how ferromagnetic resonance can characterize spin-torque vectors at an Fe-MgO interface.
