第1回物理工学科教室談話会[Dr. Samuel H. Moody・5/26(月)11:00～]

講　師：Dr. Samuel H. Moody
所　属：Postdoctoral Researcher, Center for Neutron and Muon Research, Paul Scherrer Institute, Switzerland
題　目：The Magnetoelectric Deflection Effect
日　時：2025 年 5 月 26 日(月)11:00~
Date and Time: May 26, 2025 (Monday) 11:00-
場　所：工 6 号館 3 階セミナー室 A (対面のみ)
Place: Seminar Room A, 3rd floor, Engineering Bldg. 6 (in-person only)

Abstract:
Magnetoelectric materials, where magnetic and electric degrees of freedom are intertwined, offer a rich playground for both fundamental physics and potential applications — from ultra-low-energy memory devices to new classes of sensors. In these systems, applying an electric field induces changes in the magnetic structure, governed by underlying magnetoelectric couplings.
In this talk, I will present the experimental discovery of a new type of magnetoelectric response in a chiral magnetoelectric material. Here, we find that applying an electric field causes the propagation direction of an incommensurate magnetic spiral to deflect along deterministic, controllable trajectories. Using a combination of experimental data and theoretical modelling, we show that this behaviour originates from the interplay between competing magnetocrystalline anisotropies and the coupling between the applied electric field and the material’s intrinsic polarisation. Intriguingly, our model predicts the onset of distinct nonlinear regimes of spiral deflection under varying electric and magnetic fields.
I will discuss how these findings open new opportunities for tuning macroscopic magnetisation and polarisation on demand, and I will outline some ideas for how such controlled spiral manipulation could be exploited in future device concepts, including reconfigurable magnetic textures for
information storage and logic applications.

紹介教員：ヒルシュベルガー マックス 准教授、上田 健太郎 講師（物理工学専攻・量子相エレクトロニクス研究センター）