科学的発見への中道を追求(Pursuing the middle path to scientific discovery)

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2024-07-31 アルゴンヌ国立研究所(ANL)

科学的発見への中道を追求(Pursuing the middle path to scientific discovery)
The image on the right shows the alignments of dipole directions in mesoscale structures within region of the relaxor ferroeletric material shown in the left image. (Image by Argonne National Laboratory.)

科学者たちは、電圧で形状が変化する薄膜材料の特性を解明しました。この発見はナノスケールとミクロスケールの理解を結びつけ、将来の技術に新たな可能性をもたらします。米国エネルギー省のアルゴンヌ国立研究所とライス大学、ローレンス・バークレー国立研究所の協力で、このリラクソル強誘電体のメゾスケール特性を電場下で研究しました。この材料は酸化物で、電場下で形状を変化させます。実験には先進光子源を用いたコヒーレントX線ナノ回折技術が使われ、ナノドメインが複雑なタイル状パターンを形成することが確認されました。このメゾスケール構造が小型電気機械デバイスの新しい設計に役立ち、エネルギー効率の良いマイクロエレクトロニクスの開発に貢献する可能性があります。

<関連情報>

リラクサー強誘電体における階層的極性積層体の不均一電界応答(Heterogeneous field response of hierarchical polar laminates in relaxor ferroelectrics)

Hao Zheng, Tao Zhou, Dina Sheyfer, Jieun Kim, […], and Yue Cao
Science  Published:27 Jun 2024
DOI:https://doi.org/10.1126/science.ado4494

Editor’s summary

Relaxor ferroelectrics are a class of materials that have an attractive polarization response to an external electric field. This property is attractive for a wide range of potential applications. These materials have small domains of different electrical polarization that allow efficient polarization switching of the material. Zheng et al. used x-ray coherent nanodiffraction to determine how these nanodomains are organized at the scale of hundreds of nanometers. The domains organized themselves into what the authors call nanolaminates, which are important for how the material responds at a microscopic level to changes in the electric field. —Brent Grocholski

Abstract

Understanding the microscopic origin of the superior electromechanical response in relaxor ferroelectrics requires knowledge not only of the atomic-scale formation of polar nanodomains (PNDs) but also the rules governing the arrangements and stimulated response of PNDs over longer distances. Using x-ray coherent nanodiffraction, we show the staggered self-assembly of PNDs into unidirectional mesostructures that we refer to as polar laminates in the relaxor ferroelectric 0.68PbMg1/3Nb2/3O3-0.32PbTiO3 (PMN-0.32PT). We reveal the highly heterogeneous electric-field–driven responses of intra- and interlaminate PNDs and establish their correlation with the local strain and the nature of the PND walls. Our observations highlight the critical role of hierarchical lattice organizations on macroscopic material properties and provide guiding principles for the understanding and design of relaxors and a wide range of quantum and functional materials.

1700応用理学一般
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