JOPSS:検索結果一覧

検索結果：　13 件中 1件目～13件目を表示

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

論文

The Damage analysis for irradiation tolerant spin-driven thermoelectric device based on single-crystalline YFeO $_{12}$ /Pt heterostructures

家田淳一; 岡安悟; 針井一哉*; 小畠雅明; 吉井賢資; 福田竜生; 石田真彦*; 齊藤英治

IEEE Transactions on Magnetics, 58(8), p.1301106_1 - 1301106_6, 2022/08

https://doi.org/10.1109/TMAG.2022.3145888

被引用回数：1 パーセンタイル：22.45(Engineering, Electrical & Electronic)

スピンゼーベック効果(SSE)に基づくスピン駆動熱電(STE)デバイスと、熱源としての放射性同位元素の組み合わせは、宇宙探査機の電源などの応用における次世代の発電方法としての可能性を秘めている。しかし、スピン熱電デバイスの照射耐性を示す利用可能な知識は非常に限られている。重イオンビーム加速器と硬X線光電子分光法(HAXPES)測定を使用した分析を通じて、YFeO $_{12}$ /Ptヘテロ構造に基づく典型的なSTEデバイスが高エネルギー重イオンビームの照射に対する耐性を持つことを検証する。使用済み核燃料の表面から放出される核分裂生成物による累積損傷をモデル化した320MeVの金イオンビームを使用し、線量レベルを変えることにより、SSE要素の熱電および磁気特性が $10^{10}$ イオン/cmフルエンスまでのイオン照射線量の影響を受けず、イオントラックがサンプル表面をほぼ完全に覆う約 $10^{12}$ イオン/cmでSSE信号が消滅することを確認した。さらに、HAXPES測定は、YFeO $_{12}$ /Pt界面への影響を理解するために実行した。HAXPES測定は、SSE信号を減少させる化学反応が照射線量の増加とともに強化されることを示唆している。過酷な環境使用に適用できるより優れたSTEデバイスを開発するために、YFeO $_{12}$ /Ptで損傷分析の現在の理解を共有したい。

論文

Tolerance of spin-Seebeck thermoelectricity against irradiation by swift heavy ions

岡安悟; 針井一哉*; 小畠雅明; 吉井賢資; 福田竜生; 石田真彦*; 家田淳一; 齊藤英治

Journal of Applied Physics, 128(8), p.083902_1 - 083902_7, 2020/08

AA2020-0071.pdf:0.69MB

https://doi.org/10.1063/5.0014229

被引用回数：3 パーセンタイル：19.49(Physics, Applied)

The ion-irradiation tolerance of thermoelectric devices based on the spin Seebeck effect (SSE) was investigated by using 320 MeV gold ion (Au $^{24+}$ ) beams modeling cumulative damages due to fission products emitted from the surface of spent nuclear fuels. For this purpose, prototypical Pt/YFeO $_{12}$ /GdGaO $_{12}$ SSE elements were irradiated with varying the dose level at room temperature and measured the SSE voltage of them. We confirmed that the thermoelectric and magnetic properties of the SSE elements are not affected by the ion-irradiation up to $10^{10}$ ions/cm fluence and that the SSE signal is extinguished around $10^{12}$ ions/cm, in which the ion tracks almost fully cover the sample surface. We also performed the hard X-ray photoemission spectroscopy (HAXPES) measurements to understand the effects at the interface of Pt/YFeO $_{12}$ . The HAXPES measurements suggest that the chemical reaction that diminishes the SSE signals is enhanced with the increase of the irradiation dose. The present study demonstrates that SSE-based devices are applicable to thermoelectric generation even in harsh environments for a long time period.

論文

Identification of advanced spin-driven thermoelectric materials via interpretable machine learning

岩崎悠真*; 澤田亮人*; Stanev, V.*; 石田真彦*; 桐原明宏*; 大森康智*; 染谷浩子*; 竹内一郎*; 齊藤英治; 萬伸一*

npj Computational Materials (Internet), 5, p.103_1 - 103_6, 2019/10

https://doi.org/10.1038/s41524-019-0241-9

被引用回数：47 パーセンタイル：87.87(Chemistry, Physical)

Machine learning is becoming a valuable tool for scientific discovery. Particularly attractive is the application of machine learning methods to the field of materials development, which enables innovations by discovering new and better functional materials. To apply machine learning to actual materials development, close collaboration between scientists and machine learning tools is necessary. However, such collaboration has been so far impeded by the black box nature of many machine learning algorithms. It is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and physics. Here, we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts (FAB/HMEs). Based on prior knowledge of material science and physics, we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric materials. Guided by this, we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric material. This material shows the largest thermopower to date.

論文

Machine-learning guided discovery of a new thermoelectric material

岩崎悠真*; 竹内一郎*; Stanev, V.*; Gilad Kusne, A.*; 石田真彦*; 桐原明宏*; 井原和紀*; 澤田亮人*; 寺島浩一*; 染谷浩子*; et al.

Scientific Reports (Internet), 9, p.2751_1 - 2751_7, 2019/02

https://doi.org/10.1038/s41598-019-39278-z

被引用回数：61 パーセンタイル：92.99(Multidisciplinary Sciences)

Thermoelectric technologies are becoming indispensable in the quest for a sustainable future. Recently, an emerging phenomenon, the spin-driven thermoelectric effect (STE), has garnered much attention as a promising path towards low cost and versatile thermoelectric technology with easily scalable manufacturing. However, progress in development of STE devices is hindered by the lack of understanding of the fundamental physics and materials properties responsible for the effect. In such nascent scientific field, data-driven approaches relying on statistics and machine learning, instead of more traditional modeling methods, can exhibit their full potential. Here, we use machine learning modeling to establish the key physical parameters controlling STE. Guided by the models, we have carried out actual material synthesis which led to the identification of a novel STE material with a thermopower an order of magnitude larger than that of the current generation of STE devices.

論文

Gamma radiation resistance of spin Seebeck devices

Yagmur, A.*; 内田健一*; 井原和紀*; 井岡郁夫; 吉川貴史*; 小野円佳*; 遠藤純一*; 柏木王明*; 中島哲也*; 桐原明宏*; et al.

Applied Physics Letters, 109(24), p.243902_1 - 243902_4, 2016/12

https://doi.org/10.1063/1.4971976

被引用回数：3 パーセンタイル：14.94(Physics, Applied)

スピンゼーベック効果(SSE)に基づく熱電素子の線抵抗性を調べるため、約310 $^{5}$ Gyの線照射試験を実施した。SSE素子には、Pt/Ni $_{0.2}$ Zn $_{0.3}$ Fe $_{2.5}$ O $_{4}$ /GlassとPt/Bi $_{0.1}$ Y $_{2.9}$ Fe $_{5}$ O $_{12}$ /Gd $_{3}$ Ga $_{5}$ O $_{12}$ を用いた。SSE素子の熱電特性,磁気特性、構造は、線照射により影響されないことを確認した。この結果は、SSE素子が厳しい照射環境でさえ熱電素子として適用可能なことを示した。

論文

Thermoelectric generation based on spin Seebeck effects

内田健一*; 安立裕人; 吉川貴史*; 桐原明宏*; 石田真彦*; 萬伸一*; 前川禎通; 齊藤英治*

Proceedings of the IEEE, 104(10), p.1946 - 1973, 2016/10

https://doi.org/10.1109/JPROC.2016.2535167

被引用回数：213 パーセンタイル：99.2(Engineering, Electrical & Electronic)

The spin Seebeck effect (SSE) refers to the generation of a spin current as a result of a temperature gradient in magnetic materials including insulators. The SSE is applicable to thermoelectric generation because the thermally generated spin current can be converted into a charge current via spin-orbit interaction in conductive materials adjacent to the magnets. The insulator-based SSE device exhibits unconventional characteristics potentially useful for thermoelectric applications, such as simple structure, device-design exibility, and convenient scaling capability. In this article, we review recent studies on the SSE from the viewpoint of thermoelectric applications.

論文

Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films

桐原明宏*; 近藤幸一*; 石田真彦*; 井原和紀*; 岩崎悠真*; 染谷浩子*; 松葉明日華*; 内田健一*; 齊藤英治; 山本直治*; et al.

Scientific Reports (Internet), 6, p.23114_1 - 23114_7, 2016/03

https://doi.org/10.1038/srep23114

被引用回数：62 パーセンタイル：90.69(Multidisciplinary Sciences)

ヒートフローセンシングは、将来的にスマート熱管理の重要な技術要素となることが期待されている。従来、ゼーベック効果に基づく熱電変換技術は、熱の流れを電圧に変換することによって熱流を測定するために使用されてきた。しかし、ユビキタス・ヒートフロー可視化のためには、非常に低い熱抵抗を有する薄く柔軟なセンサが非常に望まれている。近年、別のタイプの熱電効果である縦スピンゼーベック効果が大きな関心を集めている。これは縦スピンゼーベック効果が、単純な薄膜デバイス構造のような熱電アプリケーションにとって有利な機能を潜在的に提供するためである。ここでは、縦スピンゼーベック効果ベースのフレキシブル熱電シートを紹介する。このシートは、熱流検出の用途に特に適している。この熱電シートは、「フェライトめっき」として知られているスプレーコーティング法を用いてフレキシブルプラスチックシート上に形成されたNi $_{0.2}$ Zn $_{0.3}$ Fe $_{2.5}$ Oフィルムを含んでいる。実験結果は、膜面に垂直に配向した柱状結晶構造を有するフェライトめっき膜が、曲げ可能な縦スピンゼーベック効果ベースのセンサに適した独特の一次元スピン流導体として機能することを示唆している。この新しく開発された薄い熱電シートは、熱流の本来の流れを妨げることなく、さまざまな形の熱源に取り付けられ、多目的な熱流の測定と管理につながる。

論文

Enhancement of spin-Seebeck effect by inserting ultra-thin Fe $_{70}$ Cu $_{30}$ interlayer

菊池大介*; 石田真彦*; 内田健一*; Qiu, Z.*; Murakami, T.*; 齊藤英治

Applied Physics Letters, 106(8), p.082401_1 - 082401_4, 2015/02

https://doi.org/10.1063/1.4913531

被引用回数：32 パーセンタイル：75.48(Physics, Applied)

We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe $_{70}$ Cu $_{30}$ /BiY $_{2}$ Fe $_{5}$ O $_{12}$ (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe $_{70}$ Cu $_{30}$ interlayer. This enhancement decays sharply with increasing the FeCu thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe $_{70}$ Cu $_{30}$ interlayer. Combined with control experiments using Pt/Fe $_{70}$ Cu $_{30}$ devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe $_{70}$ Cu $_{30}$ /BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

論文

Longitudinal spin Seebeck effect; From fundamentals to applications

内田健一*; 石田真彦*; 吉川貴史*; 桐原明宏*; 村上朝夫*; 齊藤英治

Journal of Physics; Condensed Matter, 26(34), p.343202_1 - 343202_15, 2014/08

https://doi.org/10.1088/0953-8984/26/34/343202

被引用回数：203 パーセンタイル：84.49(Physics, Condensed Matter)

The spin Seebeck effect refers to the generation of spin voltage as a result of a temperature gradient in ferromagnetic or ferrimagnetic materials. When a conductor is attached to a magnet under a temperature gradient, the thermally generated spin voltage in the magnet injects a spin current into the conductor, which in turn produces electric voltage owing to the spin-orbit interaction. The spin Seebeck effect is of increasing importance in spintronics, since it enables direct generation of a spin current from heat and appears in a variety of magnets ranging from metals and semiconductors to insulators. Recent studies on the spin Seebeck effect have been conducted mainly in paramagnetic metal/ferrimagnetic insulator junction systems in the longitudinal configuration in which a spin current flowing parallel to the temperature gradient is measured. This "longitudinal spin Seebeck effect" (LSSE) has been observed in various sample systems and exclusively established by separating the spin-current contribution from extrinsic artefacts, such as conventional thermoelectric and magnetic proximity effects. The LSSE in insulators also provides a novel and versatile pathway to thermoelectric generation in combination of the inverse spin-Hall effects. In this paper, we review basic experiments on the LSSE and discuss its potential thermoelectric applications with several demonstrations.

論文

Spin-current-driven thermoelectric coating

桐原明宏*; 内田健一*; 梶原瑛祐*; 石田真彦*; 中村泰信*; 眞子隆志*; 齊藤英治; 萬伸一*

Nature Materials, 11(8), p.686 - 689, 2012/08

https://doi.org/10.1038/nmat3360

被引用回数：239 パーセンタイル：98.59(Chemistry, Physical)

Energy harvesting technologies, which generate electricity from environmental energy, have been attracting great interest because of their potential to power ubiquitously deployed sensor networks and mobile electronics. Of these technologies, thermoelectric (TE) conversion is a particularly promising candidate, because it can directly generate electricity from the thermal energy that is available in various places. Here we show a novel TE concept based on the spin Seebeck effect, called "spin-thermoelectric (STE) coating", which is characterized by a simple film structure, convenient scaling capability, and easy fabrication. The STE coating, with a 60-nm-thick bismuth-substituted yttrium iron garnet (Bi:YIG) film, is applied by means of a highly efficient process on a non-magnetic substrate. Notably, spin-current-driven TE conversion is successfully demonstrated under a temperature gradient perpendicular to such an ultrathin STE-coating layer (amounting to only 0.01% of the total sample thickness). We also show that the STE coating is applicable even on glass surfaces with amorphous structures. Such a versatile implementation of the TE function may pave the way for novel applications making full use of omnipresent heat.

口頭

スピンゼーベック効果素子の高エネルギー重イオン照射耐性

岡安悟; 家田淳一; 針井一哉*; 小野正雄*; 小畠雅明; 福田竜生; 吉井賢資; 石田真彦*; 齊藤英治

no journal, ,

放射線に強いとされるスピントロニクス材料の原子力分野での応用を目指し、スピンゼーベック効果(SSE)素子へ高エネルギー重イオン照射を行い、その耐用限度を調べた。その結果、使用済み核燃料間近の過酷な環境下でも十分な性能を維持する見通しを得た。この素材が耐放射線特性に優れたものであれば、同位体電池(原子力電池)への応用や使用済み燃料からの廃熱利用へと利用できる分野が広がると期待できる。

口頭

スピン熱電素子の耐ガンマ線照射耐性

岡安悟; 武山昭憲*; 大島武*; 針井一哉*; 家田淳一; 石田真彦*; 齊藤英治

no journal, ,

スピン-エネルギー変換材料科学研究グループでは放射線に強いとされるスピントロニクス材料の原子力分野での応用を目指している。前回の学会ではスピン熱電素子の耐重イオン照射特性について調べた。素子は重イオン照射による円柱状欠陥形成でダメージを受けるが未照射部分は健全性を保ち続けること、また使用済み核燃料キャスク周辺での利用で十分な寿命を有することを報告した。今回は耐ガンマ線照射線特性について報告する。同素子へのガンマ線照射に関してはYagmurらの論文で、0.3MGyまでの照射で素子の健全性が保たれることが報告されている、我々はさらに過酷な環境下での使用を想定し、1MGyまでの室温ガンマ線照射、および150 $^{circ}$ Cでの照射を行ったのでその結果を報告する。

口頭

Irradiation tolerance of spin-driven thermoelectric device against gamma-rays

家田淳一; 岡安悟; 武山昭憲*; 針井一哉*; 大島武*; 石田真彦*; 齊藤英治

no journal, ,

We investigate irradiation tolerance against gamma-rays of a prototypical spin-driven thermoelectric (STE) device based on YFeO $_{12}$ /Pt heterostructures. The past study has proved that the STE device was rad-hard against the gamma-irradiation dose up to 0.3 MGy. In this study, we assess the radiation hardness in severer environments, such as higher dose levels, higher ambient temperatures, and water steam, assuming the future RTG usage near the spent nuclear fuel storage. We show that the YFeO $_{12}$ /Pt STE device has tolerance to irradiation of gamma rays up to 0.9 MGy even at 150 C. On the other hand, we observe the performance degradation of the STE device by the gamma-irradiation under the water steam. From a control experiment without gamma-rays, the irradiation is irrelevant, and the damage is caused solely by the water steam effect. To avoid the damage, it is found that the thicker Pt film (10 nm) in the STE device is effective. Therefore, it was clarified that the STE device has fundamentally high resistance to gamma rays.