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Daichi Chiba - One of the best experts on this subject based on the ideXlab platform.

  • Electric Field Effect on magnetic moments in co ultra thin films deposited on pt
    Applied Physics Letters, 2021
    Co-Authors: Aya Obinata, Daichi Chiba, F Matsukura, Takeshi Koyama, Kohji Nakamura
    Abstract:

    This study investigates the Electric-Field Effect on magnetic moments in perpendicularly magnetized Co ultra-thin films on a Pt underlayer. By applying Electric Fields to the Co surface through MgO/HfO2 insulating layers, we determined the change in the magnetic moment per one Electrically increased electron. From systematic experiments at temperatures much below the Curie temperature, we found that the sign and the magnitude of the change depend on the nominal Co thickness tCo: the change nearly equals to −1 μB/electron for tCo ∼ 0.45 nm and more than +1 μB/electron at tCo ∼ 0.2 nm. The former value is consistent with the expectation from the celebrated Slater–Pauling curve. The latter value implies that one needs to consider some Effects characteristic to Pt/Co system with extremely small tCo. The calculated band structures suggest that the intermixing between Co and Pt is related to the observed deviation from the Slater–Pauling curve with decreasing tCo.

  • Electric Field Effect on the magnetic domain wall creep velocity in pt co pd structures with different co thicknesses
    Applied Physics Letters, 2020
    Co-Authors: Tomohiro Koyama, Junichi Ieda, Daichi Chiba
    Abstract:

    The Electric Field (EF) modulation of magnetic domain wall (DW) creep velocity v in the Pt/Co/Pd structure with perpendicular magnetic anisotropy (MA) has been studied. The structures with different Co thicknesses tCo up to ∼1 nm are investigated. In all samples, applying a gate voltage induces a clear change in v. Thicker samples provide a higher v modulation efficiency, and the v modulation magnitude of more than a factor of 100 times is observed in the thickest tCo of 0.98 nm. The parameter characterizing the creep motion is significantly affected by the EF, resulting in the modulation of v. Unlike the v case, the MA modulation efficiency decreases with increasing tCo. The present results are discussed based on the EF-induced change in the interfacial Dzyaloshinskii–Moriya interaction (iDMI), which has been recently demonstrated in the same structure, and tCo dependence of the DW energy. The tCo dependence of the v modulation suggests that the EF Effect on the iDMI is more important than the MA.

  • Electric Field Effect on magnetic anisotropy in pt co pd mgo structures deposited on gaas and si substrates
    Applied Physics Express, 2018
    Co-Authors: Yohei Hayashi, Kazumoto Miwa, Tomohiro Koyama, Shimpei Ono, Takamasa Hirai, Yuki Hibino, Hideo Ohno, F Matsukura, Daichi Chiba
    Abstract:

    We investigate the Electric-Field Effect on the magnetic anisotropy in perpendicularly magnetized Pt/Co/Pd/MgO structures deposited on GaAs and Si substrates as a function of temperature. An Electric Field is applied to the Pd surface through a 2-nm-thick insulating MgO layer by forming an Electric double layer using an ionic liquid. We find that the Electric-Field dependence of the anisotropy is similar but clearly different between the two samples at low temperatures. The difference is expected to be related to the difference in the internal strain of the two structures.

  • Electrical control of superparamagnetism
    Applied Physics Express, 2017
    Co-Authors: Kihiro Yamada, Haruka Kakizakai, Kazumoto Miwa, Fuyuki Ando, Mio Ishibashi, Takahiro Moriyama, Tomohiro Koyama, Daichi Chiba
    Abstract:

    The Electric Field control of superparamagnetism is realized using a Cu/Ni system, in which the deposited Ni shows superparamagnetic behavior above the blocking temperature. An Electric double-layer capacitor (EDLC) with the Cu/Ni electrode and a nonmagnetic counter electrode is fabricated to examine the Electric Field Effect on magnetism in the magnetic electrode. By changing the voltage applied to the EDLC, the blocking temperature of the system is clearly modulated.

  • peculiar temperature dependence of Electric Field Effect on magnetic anisotropy in co pd mgo system
    Applied Physics Letters, 2016
    Co-Authors: Yuki Hibino, Kazumoto Miwa, Tomohiro Koyama, Takamasa Hirai, Aya Obinata, F Matsukura, H Ohno, Daichi Chiba
    Abstract:

    We report on the temperature dependence of the magnetic anisotropy in Co/Pd/MgO system, in which magnetic moment in Pd is induced by the magnetic proximity Effect. We demonstrate that the magnetic anisotropy is modulated by applying an Electric Field to the Pd surface. At temperatures below 100 K, we find the nonlinear Electric-Field dependence of the anisotropy with the sign reversal. We obtain a huge anisotropy modulation efficiency of ∼1600 fJ/V m at 10 K.

Zhen Zhou - One of the best experts on this subject based on the ideXlab platform.

  • atomic interface engineering and Electric Field Effect in ultrathin bi2moo6 nanosheets for superior lithium ion storage
    Advanced Materials, 2017
    Co-Authors: Yang Zheng, Tengfei Zhou, Xudong Zhao, Wei Kong Pang, Hong Gao, Zhen Zhou, Huakun Liu, Zaiping Guo
    Abstract:

    Ultrathin 2D materials can offer promising opportunities for exploring advanced energy storage systems, with satisfactory electrochemical performance. Engineering atomic interfaces by stacking 2D crystals holds huge potential for tuning material properties at the atomic level, owing to the strong layer-layer interactions, enabling unprecedented physical properties. In this work, atomically thin Bi2 MoO6 sheets are acquired that exhibit remarkable high-rate cycling performance in Li-ion batteries, which can be ascribed to the interlayer coupling Effect, as well as the 2D configuration and intrinsic structural stability. The unbalanced charge distribution occurs within the crystal and induces built-in Electric Fields, significantly boosting lithium ion transfer dynamics, while the extra charge transport channels generated on the open surfaces further promote charge transport. The in situ synchrotron X-ray powder diffraction results confirm the material's excellent structural stability. This work provides some insights for designing high-performance electrode materials for energy storage by manipulating the interface interaction and electronic structure.

  • atomic interface engineering and Electric Field Effect in ultrathin bi2moo6 nanosheets for superior lithium ion storage
    Advanced Materials, 2017
    Co-Authors: Yang Zheng, Tengfei Zhou, Xudong Zhao, Wei Kong Pang, Sean Li, Zhen Zhou
    Abstract:

    : Ultrathin 2D materials can offer promising opportunities for exploring advanced energy storage systems, with satisfactory electrochemical performance. Engineering atomic interfaces by stacking 2D crystals holds huge potential for tuning material properties at the atomic level, owing to the strong layer-layer interactions, enabling unprecedented physical properties. In this work, atomically thin Bi2 MoO6 sheets are acquired that exhibit remarkable high-rate cycling performance in Li-ion batteries, which can be ascribed to the interlayer coupling Effect, as well as the 2D configuration and intrinsic structural stability. The unbalanced charge distribution occurs within the crystal and induces built-in Electric Fields, significantly boosting lithium ion transfer dynamics, while the extra charge transport channels generated on the open surfaces further promote charge transport. The in situ synchrotron X-ray powder diffraction results confirm the material's excellent structural stability. This work provides some insights for designing high-performance electrode materials for energy storage by manipulating the interface interaction and electronic structure.

Yang Zheng - One of the best experts on this subject based on the ideXlab platform.

  • atomic interface engineering and Electric Field Effect in ultrathin bi2moo6 nanosheets for superior lithium ion storage
    Advanced Materials, 2017
    Co-Authors: Yang Zheng, Tengfei Zhou, Xudong Zhao, Wei Kong Pang, Hong Gao, Zhen Zhou, Huakun Liu, Zaiping Guo
    Abstract:

    Ultrathin 2D materials can offer promising opportunities for exploring advanced energy storage systems, with satisfactory electrochemical performance. Engineering atomic interfaces by stacking 2D crystals holds huge potential for tuning material properties at the atomic level, owing to the strong layer-layer interactions, enabling unprecedented physical properties. In this work, atomically thin Bi2 MoO6 sheets are acquired that exhibit remarkable high-rate cycling performance in Li-ion batteries, which can be ascribed to the interlayer coupling Effect, as well as the 2D configuration and intrinsic structural stability. The unbalanced charge distribution occurs within the crystal and induces built-in Electric Fields, significantly boosting lithium ion transfer dynamics, while the extra charge transport channels generated on the open surfaces further promote charge transport. The in situ synchrotron X-ray powder diffraction results confirm the material's excellent structural stability. This work provides some insights for designing high-performance electrode materials for energy storage by manipulating the interface interaction and electronic structure.

  • atomic interface engineering and Electric Field Effect in ultrathin bi2moo6 nanosheets for superior lithium ion storage
    Advanced Materials, 2017
    Co-Authors: Yang Zheng, Tengfei Zhou, Xudong Zhao, Wei Kong Pang, Sean Li, Zhen Zhou
    Abstract:

    : Ultrathin 2D materials can offer promising opportunities for exploring advanced energy storage systems, with satisfactory electrochemical performance. Engineering atomic interfaces by stacking 2D crystals holds huge potential for tuning material properties at the atomic level, owing to the strong layer-layer interactions, enabling unprecedented physical properties. In this work, atomically thin Bi2 MoO6 sheets are acquired that exhibit remarkable high-rate cycling performance in Li-ion batteries, which can be ascribed to the interlayer coupling Effect, as well as the 2D configuration and intrinsic structural stability. The unbalanced charge distribution occurs within the crystal and induces built-in Electric Fields, significantly boosting lithium ion transfer dynamics, while the extra charge transport channels generated on the open surfaces further promote charge transport. The in situ synchrotron X-ray powder diffraction results confirm the material's excellent structural stability. This work provides some insights for designing high-performance electrode materials for energy storage by manipulating the interface interaction and electronic structure.

Hideo Ohno - One of the best experts on this subject based on the ideXlab platform.

F Matsukura - One of the best experts on this subject based on the ideXlab platform.

  • Electric Field Effect on magnetic moments in co ultra thin films deposited on pt
    Applied Physics Letters, 2021
    Co-Authors: Aya Obinata, Daichi Chiba, F Matsukura, Takeshi Koyama, Kohji Nakamura
    Abstract:

    This study investigates the Electric-Field Effect on magnetic moments in perpendicularly magnetized Co ultra-thin films on a Pt underlayer. By applying Electric Fields to the Co surface through MgO/HfO2 insulating layers, we determined the change in the magnetic moment per one Electrically increased electron. From systematic experiments at temperatures much below the Curie temperature, we found that the sign and the magnitude of the change depend on the nominal Co thickness tCo: the change nearly equals to −1 μB/electron for tCo ∼ 0.45 nm and more than +1 μB/electron at tCo ∼ 0.2 nm. The former value is consistent with the expectation from the celebrated Slater–Pauling curve. The latter value implies that one needs to consider some Effects characteristic to Pt/Co system with extremely small tCo. The calculated band structures suggest that the intermixing between Co and Pt is related to the observed deviation from the Slater–Pauling curve with decreasing tCo.

  • Electric Field Effect on magnetic anisotropy in pt co pd mgo structures deposited on gaas and si substrates
    Applied Physics Express, 2018
    Co-Authors: Yohei Hayashi, Kazumoto Miwa, Tomohiro Koyama, Shimpei Ono, Takamasa Hirai, Yuki Hibino, Hideo Ohno, F Matsukura, Daichi Chiba
    Abstract:

    We investigate the Electric-Field Effect on the magnetic anisotropy in perpendicularly magnetized Pt/Co/Pd/MgO structures deposited on GaAs and Si substrates as a function of temperature. An Electric Field is applied to the Pd surface through a 2-nm-thick insulating MgO layer by forming an Electric double layer using an ionic liquid. We find that the Electric-Field dependence of the anisotropy is similar but clearly different between the two samples at low temperatures. The difference is expected to be related to the difference in the internal strain of the two structures.

  • Electric Field Effect on spin wave resonance in a nanoscale cofeb mgo magnetic tunnel junction
    Applied Physics Letters, 2017
    Co-Authors: Takaaki Dohi, F Matsukura, Hideo Ohno
    Abstract:

    We investigate the Electric-Field Effect on the exchange stiffness constant in a CoFeB/MgO junction through the observation of the spin-wave resonance in a nanoscale magnetic tunnel junction. We evaluate the Electric-Field dependence of the stiffness constant from the separation between resonance Fields for the Kittel and spin-wave modes under Electric Fields. The obtained stiffness constant increases when the interfacial electron density is decreased. This dependence is consistent with that determined from the observation of Electric-Field dependent domain structures.

  • peculiar temperature dependence of Electric Field Effect on magnetic anisotropy in co pd mgo system
    Applied Physics Letters, 2016
    Co-Authors: Yuki Hibino, Kazumoto Miwa, Tomohiro Koyama, Takamasa Hirai, Aya Obinata, F Matsukura, H Ohno, Daichi Chiba
    Abstract:

    We report on the temperature dependence of the magnetic anisotropy in Co/Pd/MgO system, in which magnetic moment in Pd is induced by the magnetic proximity Effect. We demonstrate that the magnetic anisotropy is modulated by applying an Electric Field to the Pd surface. At temperatures below 100 K, we find the nonlinear Electric-Field dependence of the anisotropy with the sign reversal. We obtain a huge anisotropy modulation efficiency of ∼1600 fJ/V m at 10 K.

  • Electric Field induced ferromagnetic resonance in a cofeb mgo magnetic tunnel junction under dc bias voltages
    Applied Physics Letters, 2014
    Co-Authors: Martin Gajek, Daniel C Worledge, F Matsukura, Hideo Ohno
    Abstract:

    We measure homodyne-detected ferromagnetic resonance (FMR) induced by the Electric-Field Effect in a CoFeB/MgO/CoFeB magnetic tunnel junction (MTJ) with perpendicular magnetic easy axis under dc bias voltages up to 0.1 V. From the bias dependence of the resonant frequency, we find that the first order perpendicular magnetic anisotropy is modulated by the applied Electric Field, whereas the second order component is virtually independent of the Electric Field. The lineshapes of the FMR spectra are bias dependent, which are explained by the combination of Electric-Field Effect and reflection of the bias voltage from the MTJ.