東北大学研究者紹介 - Dion Troy Callum

学歴 3

Imperial College London　Department of Physics　Advanced Chracterisation of Materials Cerntre for Doctoral Training

2016年9月～ 2020年11月
UCL　London Centre for Nanotechnology　Advanced Characterisation of MAterials Centre for Doctoral Training

2016年9月～ 2020年11月
The University of Leeds　Department of Physics　Integrated Masters in Physics

2010年9月～ 2014年7月

研究キーワード 12

Kapitza pendulum
dynamic stability
isotropic magnet
reservoir computing
machine learning
ferromagnetic resonance
mumax3
micromagnetic simulation
spin waves
magnonics
artificial spin ice
nanomagnetism

研究分野 3

自然科学一般 / 磁性、超伝導、強相関系 /
自然科学一般 / 磁性、超伝導、強相関系 /
ナノテク・材料 / 材料加工、組織制御 /

受賞 3

優秀ポスター賞

2025年5月　金属材料研究所, 東北大学　双極子相互作用型3次元多層人工スピン渦アイスにおける超強マグノン–マグノン結合とカイラルスピンテクスチャ制御
サマー・プログラム

2018年6月　日本学術振興会
Best Presentation at ACM-CDT Summer Retread

Advanced Characterization of Materials Centre for Doctoral Training　Tunable Magnetisation Dynamics in Artificial Spin Ice via Shape Anisotropy Modification

論文 12

Dynamical stability by spin transfer in nearly isotropic magnets

Hidekazu Kurebayashi, Joseph Barker, Takumi Yamazaki, Varun K. Kushwaha, Kilian D. Stenning, Harry Youel, Xueyao Hou, Troy Dion, Daniel Prestwood, Gerrit E. W. Bauer, Kei Yamamoto, Takeshi Seki

Nature Materials　25　2026年3月4日
出版者・発行元： Springer Science and Business Media LLC
DOI： 10.1038/s41563-026-02510-z 　

ISSN：1476-1122

eISSN：1476-4660

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Abstract Spin transfer torques (STTs) control magnetization by electric currents, enabling a range of nano-scale spintronic applications. They can destabilize the equilibrium magnetization state by counteracting magnetic relaxation. Here we maximize the STT effect through a dedicated growth-annealing protocol for CoFeB thin films, such that magnetic anisotropies originating from the interface and shape almost cancel each other. The nearly isotropic magnets enable low-current dynamical stabilization of the magnetization in the direction opposite to an applied magnetic field, thereby realizing a spintronic analogue of the Kapitza pendulum. In an intermediate current regime, the STT drives large magnetization vector fluctuations that cover the entire Bloch sphere. The continuous variable associated with the stochastic magnetization direction may serve as a resource for probabilistic computing and neuromorphic hardware. Our results establish isotropic magnets as a platform to study as-yet-uncharted, far-from-equilibrium spin dynamics including anti-magnonics, with promising implications for unconventional computing paradigms.
Thickness dependence on dynamical spin injection driven by thermal effects in CoFeB/Pt bilayer

Sora Obinata, Troy Dion, Riku Iimori, Takashi Kimura

Scientific Reports　14　(1)　2024年12月

DOI： 10.1038/s41598-024-75683-9 　

eISSN：2045-2322
Ultrastrong magnon-magnon coupling and chiral spin-texture control in a dipolar 3D multilayered artificial spin-vortex ice

Troy Dion, Kilian D. Stenning, Alex Vanstone, Holly H. Holder, Rawnak Sultana, Ghanem Alatteili, Victoria Martinez, Mojtaba Taghipour Kaffash, Takashi Kimura, Rupert F. Oulton, Will R. Branford, Hidekazu Kurebayashi, Ezio Iacocca, M. Benjamin Jungfleisch, Jack C. Gartside

Nature Communications　15　(1)　2024年5月14日
出版者・発行元： Springer Science and Business Media LLC
DOI： 10.1038/s41467-024-48080-z 　

eISSN：2041-1723

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Abstract Strongly-interacting nanomagnetic arrays are ideal systems for exploring reconfigurable magnonics. They provide huge microstate spaces and integrated solutions for storage and neuromorphic computing alongside GHz functionality. These systems may be broadly assessed by their range of reliably accessible states and the strength of magnon coupling phenomena and nonlinearities. Increasingly, nanomagnetic systems are expanding into three-dimensional architectures. This has enhanced the range of available magnetic microstates and functional behaviours, but engineering control over 3D states and dynamics remains challenging. Here, we introduce a 3D magnonic metamaterial composed from multilayered artificial spin ice nanoarrays. Comprising two magnetic layers separated by a non-magnetic spacer, each nanoisland may assume four macrospin or vortex states per magnetic layer. This creates a system with a rich 16^N microstate space and intense static and dynamic dipolar magnetic coupling. The system exhibits a broad range of emergent phenomena driven by the strong inter-layer dipolar interaction, including ultrastrong magnon-magnon coupling with normalised coupling rates of $$\frac{\Delta f}{\nu }=0.57$$, GHz mode shifts in zero applied field and chirality-control of magnetic vortex microstates with corresponding magnonic spectra.
Ultrastrong Magnon-Magnon Coupling and Chiral Symmetry Breaking in a 3D Magnonic Metamaterial

Troy Dion, Killian Stenning, Alex Vanstone, Holly Holder, Rawnak Sultana, Ghanem Alatteili, Victoria Martinez, Mojtaba Kaffash, Takashi Kimura, Hidekazu Kurebayashi, will branford, Ezio Iacocca, M. Benjamin Jungfleisch, Jack C Gartside

2023年8月19日

DOI： 10.21203/rs.3.rs-3123082/v1 　

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<jats:title>Abstract</jats:title> <jats:p>Strongly-interacting nanomagnetic arrays are ideal systems for exploring the frontiers of magnonic control. They provide functional reconfigurable platforms and attractive technological solutions across storage, GHz communications and neuromorphic computing. Typically, these systems are primarily constrained by their range of accessible states and the strength of magnon coupling phenomena. Increasingly, magnetic nanostructures have explored the benefits of expanding into three dimensions. This has broadened the horizons of magnetic microstate spaces and functional behaviours, but precise control of 3D states and dynamics remains challenging. Here, we introduce a 3D magnonic metamaterial, compatible with widely-available fabrication and characterisation techniques. By combining independently-programmable artificial spin-systems strongly coupled in the $\hat{z}$-plane, we construct a reconfigurable 3D metamaterial with an exceptionally high $16^N$ microstate space and intense static and dynamic magnetic coupling. The system exhibits a broad range of emergent phenomena driven by high-intensity inter-layer dipolar interaction, including ultrastrong magnon-magnon coupling with normalised coupling rates of $\frac{\Delta \omega}{\gamma} = 0.57$ and magnon-magnon cooperativity up to $C = 126.4$, GHz mode shifts in zero applied field and chirality-selective magneto-toroidal microstate programming and corresponding magnonic spectral control.</jats:p>
Reconfigurable training and reservoir computing in an artificial spin-vortex ice via spin-wave fingerprinting

Jack C Gartside, Kilian Stenning, Alex Vanstone, Holly Holder, Daan M. Arroo, Troy Dion, Francesco Caravelli, Hidekazu Kurebayashi, will branford

Nature Nanotechnology　2022年5月

DOI： 10.1038/s41565-022-01091-7 　

ISSN：1748-3387 1748-3395
Observation and control of collective spin-wave mode hybridization in chevron arrays and in square, staircase, and brickwork artificial spin ices

Troy Dion, Jack C Gartside, Alex Vanstone, Kilian Stenning, Daan M. Arroo, Hidekazu Kurebayashi, will branford

Physical Review Research　2022年2月11日

DOI： 10.1103/physrevresearch.4.013107 　

ISSN：2643-1564
Coupling microwave photons to topological spin textures in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>Cu</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi>OSeO</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:math>

Safe Khan, Oscar Lee, T. Dion, Christoph Zollitsch, S. Seki, Y. Tokura, Jonathan Breeze, Hidekazu Kurebayashi

Physical Review B　2021年9月3日

DOI： 10.1103/physrevb.104.l100402 　

ISSN：2469-9950 2469-9969
Reconfigurable magnonic mode-hybridisation and spectral control in a bicomponent artificial spin ice

Jack C Gartside, Alex Vanstone, Troy Dion, Kilian Stenning, Daan M. Arroo, Hidekazu Kurebayashi, will branford

Nature Communications　2021年5月3日

DOI： 10.1038/s41467-021-22723-x 　

ISSN：2041-1723

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<jats:title>Abstract</jats:title><jats:p>Strongly-interacting nanomagnetic arrays are finding increasing use as model host systems for reconfigurable magnonics. The strong inter-element coupling allows for stark spectral differences across a broad microstate space due to shifts in the dipolar field landscape. While these systems have yielded impressive initial results, developing rapid, scaleable means to access a broad range of spectrally-distinct microstates is an open research problem. We present a scheme whereby square artificial spin ice is modified by widening a ‘staircase’ subset of bars relative to the rest of the array, allowing preparation of any ordered vertex state via simple global-field protocols. Available microstates range from the system ground-state to high-energy ‘monopole’ states, with rich and distinct microstate-specific magnon spectra observed. Microstate-dependent mode-hybridisation and anticrossings are observed at both remanence and in-field with dynamic coupling strength tunable via microstate-selection. Experimental coupling strengths are found up to <jats:italic>g</jats:italic>/2<jats:italic>π</jats:italic> = 0.16 GHz. Microstate control allows fine mode-frequency shifting, gap creation and closing, and active mode number selection.</jats:p>
Magnonic Bending, Phase Shifting and Interferometry in a 2D Reconfigurable Nanodisk Crystal

Kilian Stenning, Jack C. Gartside, Troy Dion, Alexander Vanstone, Daan M. Arroo, Will R. Branford

ACS Nano　2021年1月26日

DOI： 10.1021/acsnano.0c06894 　

ISSN：1936-0851 1936-086X
Current-controlled nanomagnetic writing for reconfigurable magnonic crystals

Jack C Gartside, Son Gyo Jung, Seung Yeun Yoo, Daan M. Arroo, Alex Vanstone, Troy Dion, Kilian Stenning, will branford

Communications Physics　2020年11月30日

DOI： 10.1038/s42005-020-00487-y 　

ISSN：2399-3650

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<jats:title>Abstract</jats:title><jats:p>Strongly-interacting nanomagnetic arrays are crucial across an ever-growing suite of technologies. Spanning neuromorphic computing, control over superconducting vortices and reconfigurable magnonics, the utility and appeal of these arrays lies in their vast range of distinct, stable magnetization states. Different states exhibit different functional behaviours, making precise, reconfigurable state control an essential cornerstone of such systems. However, few existing methodologies may reverse an arbitrary array element, and even fewer may do so under electrical control, vital for device integration. We demonstrate selective, reconfigurable magnetic reversal of ferromagnetic nanoislands via current-driven motion of a transverse domain wall in an adjacent nanowire. The reversal technique operates under all-electrical control with no reliance on external magnetic fields, rendering it highly suitable for device integration across a host of magnonic, spintronic and neuromorphic logic architectures. Here, the reversal technique is leveraged to realize two fully solid-state reconfigurable magnonic crystals, offering magnonic gating, filtering, transistor-like switching and peak-shifting without reliance on global magnetic fields.</jats:p>
Tunable magnon-magnon coupling in synthetic antiferromagnets

A. Sud, Christoph Zollitsch, A. Kamimaki, Troy Dion, S. Khan, S. Iihama, S. Mizukami, H. Kurebayashi

Physical Review B　2020年9月10日

DOI： 10.1103/physrevb.102.100403 　

ISSN：2469-9950 2469-9969
Tunable magnetization dynamics in artificial spin ice via shape anisotropy modification

Dion, T., Arroo, D.M., Yamanoi, K., Kimura, T., Gartside, J.C., Cohen, L.F., Kurebayashi, H., Branford, W.R.

Physical Review B　100　(5)　2019年

DOI： 10.1103/PhysRevB.100.054433

︎全件表示 ︎最初の5件までを表示

MISC 2

Magnetic vortex writing and local reversal seeding in artificial spin-vortex ice via all-optical and surface-probe control

Holly Holder, Jack C. Gartside, Alex Vanstone, Troy Dion, Xiaofei Xiao, Kilian D. Stenning, Tingjun Zheng, Daniel Bromley, Tobias Farchy, Rupert F. Oulton, Will R. Branford

2025年5月22日

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Artificial spin-vortex ice ('ASVI') is a reconfigurable nanomagnetic metamaterial consisting of magnetic nanoislands tailored to support both Ising macrospin and vortex textures. ASVI has recently shown functional applications including reconfigurable magnonics and neuromorphic computing, where the introduction of vortex textures broadens functionality beyond conventional artificial spin ice which generally supports macrospin states. However, local control of writing vortex states in ASVI remains an open challenge. Here we demonstrate techniques for field-free magnetic vortex writing in ASVI. We expand ASVI to support metastable macrospin, single-vortex and double-vortex states. All-optical writing via focused laser illumination can locally write double-vortex textures, and surface-probe writing using an MFM tip can locally write single vortex states. We leverage this writing to tailor and explore the reconfigurable energy landscape of ASVI, demonstrating programmable local seeding of avalanche-like reversal events. The global field-free texture selective writing techniques reported here expand the suite of nanomagnetic control techniques, with a host of future applications including fundamental studies of avalanche dynamics, physical memory, and direct writing of nanomagnetic 'weights' in physical neuromorphic neural networks.
Spin wave resonance in yttrium iron garnet stripe domains

Daniel Prestwood, Chris E. A. Barker, Kilian D. Stenning, Charlie W. F. Freeman, Tianyi Wei, Takashi Kikkawa, Troy Dion, Daniel Stoeffler, Yves Henry, Matthieu Bailleul, Noora Naushad, William Griggs, Thomas Thomson, Murat Cubukcu, Jack C. Gartside, Eiji Saitoh, Will R. Branford, Hidekazu Kurebayashi

2025年5月13日

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We study a thin film yttrium iron garnet sample that exhibits magnetic stripe domains due to a small perpendicular magnetic anisotropy. Using wide-field magneto-optic Kerr effect measurements we reveal the domain pattern evolution as a function of applied field and discuss the role of the cubic anisotropy in the domain formation. Rich magnon spectra are observed in the stripe domain states, with a range of excitation conditions providing distinct spectra. The measurements are interpreted using micromagnetic simulations to provide the spatial profiles of each resonance mode. We further simulate domain patterns and resonance spectra accounting for the cubic anisotropy,with good correlation to experiment. This study highlights how non-collinear magnetic domain structures can host complex resonant behaviour in a low-damping magnetic material, with potential use in future magnonic applications.

講演・口頭発表等 15

Magnetic Kapitza: Dynamic Stability in Nearly Isotropic Magnets via Spin Transfer Torque

Troy Dion

Iwate Spintronics SChool 2026　2026年3月3日
A Brief History of Artificial Spin Ice: From Differential Fabrication to Application 招待有り

Troy Dion

IEEE AtC-AtG Magnetics Conference 2025　2025年11月18日
強い双極子結合磁性層におけるマグノン周波数コーミング

トロイディオン

2025年7月14日
双極子相互作用型3次元多層人工スピン渦アイスにおける超強マグノン–マグノン結合とカイラルスピンテクスチャ制御

トロイディオン

2025年5月28日
双極子相互作用型3次元多層人工スピン渦アイスにおける超強マグノン–マグノン結合とカイラルスピンテクスチャ制御招待有り

トロイディオン

2025年3月18日
多層人工スピンアイスにおけるマイクロ状態制御と超強結合招待有り

トロイディオン

2024年10月28日
Novel Artificial Spin Ice Geometries for Spintronics Applications

Troy Dion

Iwate Spintronics School　2024年2月14日
Reconfigurable Spin-wave Dispersion in Continuous Magnetic Layer Induced via Artificial Spin Ice Magnonic Crystal

Troy Dion

Frontiers in Artificial Spin Ice
Reconfigurable Spin-wave Dispersion in Continuous Magnetic Layer Induced via Artificial Spin Ice Magnonic Crystal

Troy Dion

Intermag 2023 Sendai　2023年5月9日
Reconfigurable Spin-wave Dispersion in Continuous Magnetic Layer Induced via Artificial Spin Ice Magnonic Crystal

Troy Dion

APS March Meeting, Las Vegas　2023年3月8日
Reconfigurable Spin-wave Dispersion in Continuous Magnetic Layer Induced via Artificial Spin Ice Magnonic Crystal

Troy Dion

APS March Meeting, Las Vegas　2023年3月7日
Collective Spin-wave Mode Hybridisation in Artificial Spin Ices

Troy Dion

International Colloquium on Magnetic Films and Surfaces, Okinawa　2022年7月12日
Angular Dependent FMR of Rotational Symmetry Broken Artificial Kagome Spin Ice

Troy Dion

Advanced Characterization of Materials Conference, Barcelona　2019年7月10日
Tunable Magnetization Dynamics in Artificial Spin Ice Via Shape Anisotropy Modification

Troy Dion

Institute of Physics Magnetism, Leeds　2019年4月8日
Angular Dependent FMR of Rotational Symmetry Broken Artificial Kagome Spin Ice

Troy Dion

Institute of Physics Magnetism, Manchester　2018年4月9日

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共同研究・競争的資金等の研究課題 2

マグノニック計算を目指したYIG/ナノ磁性体複合構造におけるスピンダイナミクス

木村崇, DION TROY

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for JSPS Fellows

研究機関：Kyushu University

2023年3月8日～ 2024年3月31日

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磁性薄膜中のスピン波は、電流に伴うジュール熱無しの超低消費電力なエレクトロニクスデバイスの実現が期待できる。しかしながら、微細加工に適した金属磁性体は、スピン波伝搬長が短い、スピン波伝搬長が長い磁性絶縁体 YIG は、微細加工が難しいなどの問題があった。本研究では、高品質な YIG 薄膜と微細加工を施した強磁性体の複合構造からなるマグノニック結晶を用いて、ニューロモルフィックコンピューティングなど従来にはない新奇な高機能電子デバイスを実現を目指す。計画通りにマイクロマグネティクスの計算を行い、分散関係の変調を確認するとともに、強磁性体の磁化配列に応じた複数の特性の再構成の実現に成功した。更に、特徴的な非相反伝搬特性と及び磁壁の伝搬に対応した急峻な共鳴特性が得られることを確認した。このように数値計算で得られた特性を実証するべく、Well-define なナノ磁性体を作製を目指した。ここで、微細パターンの微妙な構造がスピンダイナミクスに大きな影響を及ぼすので、市販の電子線描画パターン生成ソフトを用いて、電子線描画の描画条件の最適化を行った。電子線レジストやリフトオフ法においても最新の注意を行い、素子を試作したところ、極めてWell-define な素子の実現に成功した。その後、磁気力顕微鏡を交えた磁区構造の制御を行った結果、数値計算で期待される４つの磁化配列が、アレイの中に適切な確率で分布していることを確認し、印加する磁場の方向と大きさを制御することで、所望の磁区構造が得られていることを確認した。その後、YIG 薄膜上へのナノ磁性体列を作製を行う予定であったが、より簡便な成果を求めて、金属軟磁性体であるアモルファス構造のCoFeB 薄膜を用いて、スピン波デバイスを作製した。
マグノニック計算を目指したYIG/ナノ磁性体複合構造におけるスピンダイナミクス

木村崇, DION TROY

2020年11月13日～ 2023年3月31日

担当経験のある科目(授業) 5

サイエンス英会話筋トレ　九州大学
国際科学特論　九州大学
Postgraduate Teaching Assistant: Micromagnetic Simulation　Imperial College London
Postgraduate Teaching Assistant: Electronic and Electrical Engineering　UCL
A-Level Mathematics Tutoring　First Tutors