Scientifc Publications

Discover all AcouSome consortium publications including, scientific papers, posters and more.

Oxygen-defective electrostrictors for soft electromechanics

Journal: Science Advances, Vol. 10 | Issue 36 | 6 September 2024

 

Author(s): Victor Buratto Tinti, Jin Kyu Han, Valdemar Frederiksen, Huaiyu Chen, Jesper Wallentin, Innokenty Kantor, Anton Lyksborg-Andersen, Thomas Willum Hansen, Garam Bae, Wooseok Song, Eugen Stamate, Daniel Zanetti de Florio, Henrik Bruus, and Vincenzo Esposito

 

DOI: 10.1126/sciadv.adq344

 

Abstract: Electromechanical metal oxides, such as piezoceramics, are often incompatible with soft polymers due to their crystallinity requirements, leading to high processing temperatures. This study explores the potential of ceria-based thin films as electromechanical actuators for flexible electronics. Oxygen-deficient fluorites, like cerium oxide, are centrosymmetric nonpiezoelectric crystalline metal oxides that demonstrate giant electrostriction. These films, deposited at low temperatures, integrate seamlessly with various soft substrates like polyimide and PET. Ceria thin films exhibit remarkable electrostriction (M33 > 10−16 m2 V−2) and inverse pseudo-piezo coefficients (e33 > 500 pmV−1), enabling large displacements in soft electromechanical systems. Our study explores resonant and off-resonant configurations in the low-frequency regime (<1 kHz), demonstrating versatility for three-dimensional and transparent electronics. This work advances the understanding of oxygen-defective metal oxide electromechanical properties and paves the way for developing versatile and efficient electromechanical systems for applications in biomedical devices, optical devices, and beyond.

 

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Enhanced non-classical electrostriction in strained tetragonal ceria

Journal: Nature Communications, 16, Article number: 36 (2025)

 

Author(s):Simone Santucci, Milica Vasiljevic, Haiwu Zhang, Victor Buratto Tinti, Achilles Bergne, Armando A. Morin-Martinez, Sandeep Kumar Chaluvadi, Pasquale Orgiani, Simone Sanna, Anton Lyksborg-Andersen, Thomas Willum Hansen, Ivano E. Castelli, Nini Pryds & Vincenzo Esposito

 

DOI: https://doi.org/10.1038/s41467-024-55393-6

 

Abstract:Electrostriction is the upsurge of strain under an electric field in any dielectric material. Oxygen-defective metal oxides, such as acceptor-doped ceria, exhibit high electrostriction 10-17 m2V-2 values, which can be further enhanced via interface engineering at the nanoscale. This effect in ceria is “non-classical” as it arises from an intricate relation between defect-induced polarisation and local elastic distortion in the lattice. Here, we investigate the impact of mismatch strain when epitaxial Gd-doped CeO2 thin films are grown on various single-crystal substrates. We demonstrate that varying the compressive and tensile strain can fine-tune the electromechanical response. The electrostriction coefficients achieve a large M11 ≈ 3.6·10-15 m2V-2 in lattices of in-plane compressed films, i.e., a positive tetragonality (c/a-1 > 0), with stress above 3 GPa at the film/substrate interface. Chemical and structural analysis suggests that the high electrostriction stems from anisotropic distortions in the local lattice strain, which lead to constructively oriented elastic dipoles and Ce3+ electronic defects.

 

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