受賞区分：国内学会・会議・シンポジウム等の賞 

担当区分：筆頭著者,　責任著者   記述言語：英語   出版者・発行元：Journal of Materials Chemistry C  

A low-dimensional magnetic system promotes strong interactions between quantum spins and leads to fascinating quantum phenomena. To realize quantum devices based on the spin-liquid ground state, a two-dimensional magnetic system with strong spin-frustration is highly desired. A honeycomb-layered tellurate with a 3d transition metal within its slabs is a potential system that can host Kitaev quantum spin-liquid although conclusive evidence for the spin-liquid phase has not been reported to date. This might be partially due to the presence of an interslab exchange coupling between magnetic honeycomb slabs which stabilizes antiferromagnetic ordering and potentially suppresses Kitaev interactions. Here, we report the magnetic and spin frustration properties of Ag-based honeycomb layered tellurates with magnetic honeycomb slabs separated by Ag bilayers which are expected to screen the interslab exchange coupling. From magnetization measurements, we observe antiferromagnetic ordering and signatures of enhanced spin-frustration for the tellurates containing Ag-bilayers relative to other honeycomb layered tellurates without bilayers. The results might be promising for the realization of the Kitaev quantum spin liquid.

DOI： 10.1039/d3tc01915b

Web of Science

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担当区分：責任著者   記述言語：英語   出版者・発行元：Physical Review Applied  

A ferromagnetic-antiferromagnetic (FM-AFM) thin-film heterostructure is proposed to be a potential system that can induce perpendicular magnetic anisotropy (PMA) in a ferromagnet, although there are few material combinations available and the underlying mechanism is not sufficiently understood. Here, we demonstrate that the AFM phase of an Fe-Rh ordered alloy induces PMA in an adjacent Fe layer in an Fe/Fe-Rh heterostructure, which manifests itself as an additional mode of ferromagnetic resonance. The induced interfacial PMA disappears following a magnetic phase transition of Fe-Rh from the AFM to the FM state, suggesting that the AFM order is crucial for the stabilization of PMA. The absence of the additional resonance mode in an Fe/Rh/Fe-Rh control sample suggests that the PMA originates from a magnetic exchange coupling at the Fe/Fe-Rh interface. The results are promising for the development of high-density spintronic devices, in which PMA is controllable through the phase transition of Fe-Rh.

DOI： 10.1103/PhysRevApplied.19.064077

Web of Science

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記述言語：英語   出版者・発行元：Applied Physics Letters  

In recent years, antiferromagnetic materials have been attracting increasing interest for their stability in high magnetic fields and ultrafast magnetization dynamics. Since the energy scale of an interlayer exchange coupling (IEC) in a synthetic antiferromagnet (SAF) consisting of ferromagnetic/nonmagnetic/ferromagnetic multilayers is relatively smaller than that of an exchange coupling in antiferromagnetic materials, magnetic ordering of a SAF can be potentially controlled by an electric field, which is promising for energy-saving spintronic memory devices. However, an electric field-induced magnetoelastic response of SAFs on ferroelectric materials has not been sufficiently understood due to the presence of IEC that complicates magnetization dynamics. In this study, we prepare Co/Ru/Co SAFs with various amplitude of IEC on ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 substrates and systematically investigate their electric field-induced magnetoelastic response. We demonstrate that the magnetoelastic response disappears at the boundary where a switching between the antiferromagnetic and ferromagnetic IEC coupling occurs. The result provides insight into the coupling of the magnetoelastic effect and IEC and is useful in designing spintronic memory devices based on SAFs.

DOI： 10.1063/5.0151832

Web of Science

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記述言語：英語   出版者・発行元：Applied Physics Letters  

In La1−xSrxMnO3 (LSMO)/BaTiO3 (BTO) heterostructures with a multiferroic interface, an artificial modulation of the magnetic structure is observed. The saturation magnetization of La1−xSrxMnO3 changes discontinuously due to in-plane distortions caused by a structural phase transition of a BaTiO3 substrate. Polarity reversal of the external electric field also causes a reversible switching in the magnetization. The magnitude of both magnetic modulations, due to the magnetoelastic and electric field effects, is concomitantly enhanced at a critical composition x c ∼ 0.55 , locating at a border of the magnetic phase transition. The polarity-dependent change in magnetization is possibly attributed to a change in the concentration of oxygen ions at the LSMO/BTO interface, indicating that the exchange interaction is reciprocally driven from being ferromagnetic to antiferromagnetic by the electric field polarity.

DOI： 10.1063/5.0150917

Web of Science

Scopus

出版者・発行元：2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings  

Various attempts to realize electric field controlled energy-saving spintronic devices have been made in recent years. Artificial multiferroic heterostructures have attracted much attention because of its ability to control magnetization by an electric field due to the inverse magnetoelectric effect. In this study, as a new artificial multiferroic heterostructure, we investigate the electric field effects on the magnetic properties of a synthetic antiferromagnet composed of Co/Ru/Co deposited on ferroelectric (011) oriented Pb(Mg1/3Nb2/3)O3-PbTiO3. Spin-flop transition, which is characteristic of interlayer coupled synthetic antiferromagnets, is observed. The magnetic field direction at which the spin-flop behavior occurs is rotated by 90° upon the application of an electric field. The results are promising to be used in next-generation spintronic devices.

DOI： 10.1109/INTERMAGShortPapers58606.2023.10228509

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