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Lee, S.*; Nakata, Koki; Tchernyshyov, O.*; Kim, S. K.*
Physical Review B, 107(18), p.184432_1 - 184432_12, 2023/05
Times Cited Count：5 Percentile：87.72(Materials Science, Multidisciplinary)We theoretically investigate the interaction between magnons and a Skyrmion-textured domain wall in a two-dimensional antiferromagnet and elucidate the resultant properties of magnon transport. Using supersymmetric quantum mechanics, we solve the scattering problem of magnons on top of the domain wall and obtain the exact solutions of propagating and bound magnon modes. Then, we find their properties of reflection and refraction in the Skyrmion-textured domain wall, where magnons experience an emergent magnetic field due to its non-trivial spin texture-induced effective gauge field. Finally, we show that the thermal transport decreases as the domain wall's chirality increases. Our results suggest that the thermal transport of an antiferromagnet is tunable by modulating the Skyrmion charge density of the domain wall.
Yamanouchi, Michihiko*; Araki, Yasufumi; Sakai, Takaki*; Uemura, Tetsuya*; Ota, Hiromichi*; Ieda, Junichi
Science Advances (Internet), 8(15), p.eabl6192_1 - eabl6192_6, 2022/04
Times Cited Count：7 Percentile：80.16(Multidisciplinary Sciences)In a ferromagnetic Weyl metal SrRuO, a large effective magnetic field 
exerted on a magnetic domain wall (DW) by current has been reported. We show that the ratio of to current density exhibits nonmonotonic temperature dependence and surpasses those of conventional spin-transfer torques and spin-orbit torques. This enhancement is described well by topological Hall torque (THT), which is exerted on a DW by Weyl electrons emerging around Weyl points when an electric field is applied across the DW. The ratio of the arising from the THT to current density is over one order of magnitude higher than that originating from spin-transfer torques and spin-orbit torques reported in metallic systems, showing that the THT may provide a better way for energy-efficient manipulation of magnetization in spintronics devices.
Araki, Yasufumi; Watanabe, Jin*; Nomura, Kentaro*
Journal of the Physical Society of Japan, 90(9), p.094702_1 - 094702_9, 2021/09
Times Cited Count：1 Percentile：15.97(Physics, Multidisciplinary)While nodal-line semimetals with magnetism have been theoretically predicted and experimentally observed in a few compounds, idea on the relation between the magnetic order and the electronic structure is still limited. We theoretically explore the electronic structure in bulk and boundary of such a magnetic nodal-line state by introducing magnetism in topological Dirac semimetal (TDSM). TDSMs, such as 
and 
,are characterized by a pair of spin-degenerate Dirac points protected by rotational symmetries of crystals. By introducing local magnetic moments coupled to the electron spins in the lattice model of TDSM, we show that the TDSM can turn into either a Weyl semimetal or a nodal-line semimetal, which is determined by the orbital dependence in the exchange coupling and the direction of magnetization formed by the magnetic moments. In this magnetic nodal-line semimetal state, we find zero modes with drumhead-like band structure at the boundary that are characterized by the topological number of 
. Those zero modes are numerically demonstrated by introducing magnetic domain walls in the lattice model.
Jiang, N.*; Nii, Yoichi*; Arisawa, Hiroki*; Saito, Eiji; Oe, Junichiro*; Onose, Yoshinori*
Physical Review Letters, 126(17), p.177205_1 - 177205_5, 2021/04
Times Cited Count：4 Percentile：48.26(Physics, Multidisciplinary)Imai, Masaki; Chudo, Hiroyuki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Physical Review B, 102(1), p.014407_1 - 014407_5, 2020/07
Times Cited Count：6 Percentile：38.16(Materials Science, Multidisciplinary)Araki, Yasufumi
Annalen der Physik, 532(2), p.1900287_1 - 1900287_16, 2020/02
Times Cited Count：37 Percentile：88.41(Physics, Multidisciplinary)
Yamanouchi, Michihiko*; Oyamada, Tatsuro*; Sato, Koichi*; Ota, Hiromichi*; Ieda, Junichi
IEEE Transactions on Magnetics, 55(7), p.1400604_1 - 1400604_4, 2019/07
Times Cited Count：4 Percentile：27.05(Engineering, Electrical & Electronic)Fukami, Shunsuke*; Ieda, Junichi; Ohno, Hideo*
Physical Review B, 91(23), p.235401_1 - 235401_7, 2015/06
Times Cited Count：22 Percentile：66.54(Materials Science, Multidisciplinary)We study thermal stability of a magnetic domain wall pinned in nanowires made of Co/Ni multilayers, and analyze the effective volume that governs the thermal stability. We find that, above a critical wire width, the domain wall depinning is initiated by a subvolume excitation and that the critical width is dependent on the wire thickness. The obtained findings are supported by the distribution of critical current density for domain wall depinning and are qualitatively described by considering the balance between the Zeeman energy and domain wall elastic energy.
Ieda, Junichi; Yamane, Yuta*
no journal, ,
no abstracts in English
Sakai, Takaki*; Yamanouchi, Michihiko*; Araki, Yasufumi; Uemura, Tetsuya*; Ota, Hiromichi*; Ieda, Junichi
no journal, ,
Lee, S.*; Nakata, Koki; Tchernyshyov, O.*; Kim, S. K.*
no journal, ,
Using supersymmetric quantum mechanics, we solve the scattering problem of magnons on top of the domain wall and obtain the exact solutions of propagating and bound magnon modes. We then find their properties of reflection and refraction in the Skyrmion textured domain wall, where magnons experience an emergent magnetic field due to its non-trivial spin texture induced effective gauge field. Next, we show that thermal transport decreases as the domain wall's chirality increases. Finally, thermal transport of an antiferromagnet is shown to be tunable by modulating the Skyrmion charge density of the domain wall, which might be useful for realizing electrically tunable spin caloritronic devices.
