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Lee, S.*; 仲田 光樹; Tchernyshyov, O.*; Kim, S. K.*
Physical Review B, 107(18), p.184432_1 - 184432_12, 2023/05
被引用回数：5 パーセンタイル：87.72(Materials Science, Multidisciplinary)超対称量子力学に基づき、反強磁性スカーミオン構造を有する磁壁中のマグノンのトポロジカル量子輸送物性を明らかにする。スカーミオン型の磁気構造を有する磁壁中を伝搬するマグノンは、一種のゲージ場として作用する有効磁場を獲得する。そこで、この有効磁場中でのマグノンの反射・屈折現象を超対称量子力学に基づいて解析し、その伝搬および束縛マグノン状態を明らかにする。そして、ラウダウアー公式を用いて、磁壁のカイラリティが増加するにつれてマグノンによる熱流が減少することを明らかにする。本研究はスピンホール効果を活用した熱流の制御方法を理論的に提案する。
藤本 純治*; 船木 博志*; 小椎八重 航*; 松尾 衛; 前川 禎通*
IEEE Transactions on Magnetics, 58(8), p.1500407_1 - 1500407_7, 2022/08
被引用回数：0 パーセンタイル：0(Engineering, Electrical & Electronic)Motivated by the recent experiment done by Yu et al. [X. Z. Yu, et. al., Sci. Adv., 6, 25, eaaz9744 (2020)] on magnetic skyrmion creation and annihilation by electric currents in FeGe devices with a notch structure, we examine the interaction between the electric current vorticity near the notch and localized spins, and obtain three effects of the current vorticity on the localized spins. The first one is an effective Zeeman field induced by the current vorticity. This effective Zeeman field is responsible for skyrmion creation. The second effect is a vorticity-induced Dzyaloshinskii-Moriya (DM) interaction with the direction of the DM vector being parallel to the vorticity direction and is different from the vector of the intrinsic DM interaction. This vorticity-induced DM interaction makes the skyrmions distorted. The third effect is a spin current due to the gradient of the vorticity and the spin current drives the magnetic skyrmions far from the notch. Our theory opens a new path to design the magnetic textures by using structural settings.
家田 淳一; 山根 結太*; 前川 禎通
no journal, ,
When nonuniform magnetization textures such as magnetic domain walls and Skyrmions are in motion emergent electromagnetic fields acting on conduction electron spin are induced. Spinmotive force is one of the emerging effects which allows direct conversion of magnetic energy to electric voltage in magnetic nanostructures. Motivated by recent extensive studies on spin-orbitronics, in which spin-orbit couplings (SOCs) play significant roles, the concept of spinmotive force has been extended by incorporating such effects. As an important example, we investigate spinmotive force generated by the translational motion of magnetic Skyrmion. We obtain the expression for the spinmotive force, considering the Rashba and Dresselhaus SOCs as well as the so-called 
term arising from the nonadiabaticity in the electron spin dynamics. Our results reveal the dependence of the spinmotive force on the Skyrmion profile and the SOC parameters, which offers an estimation of the spinmotive force for a given experiment. The estimation of SOC contributions in spinmotive force is particularly important when one designs the so-called emergent inductor proposed in since it uses spiral magnets that are inevitably accompanied by sizable SOCs.
Lee, S.*; 仲田 光樹; Tchernyshyov, O.*; Kim, S. K.*
no journal, ,
超対称量子力学に基づき、反強磁性スカーミオン構造を有する磁壁中のマグノン輸送理論を構築する。スカーミオン型の磁気構造により、マグノンは有効ゲージ場として作用する創発磁場を獲得する。そこで、この有効磁場中でのマグノンの反射・屈折現象を超対称量子力学に基づいて解析し、その伝搬および束縛マグノン状態を明らかにする。そして、磁壁のカイラリティが増加するにつれてマグノンによる熱流が減少することをラウダウアー公式を用いて明らかにし、スピンホール効果を活用した熱流の制御方法を提案する。
