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Auteurs principaux: Piecuch, Timo, Daneu, Nina, Brock, Jeffrey A., Huang, Xiaochun, Radoševič, Tina, Müller, Arnold M., Vockenhuber, Christof, Schneider, Christof W., Lippert, Thomas, Shepelin, Nick A.
Format: Preprint
Publié: 2025
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Accès en ligne:https://arxiv.org/abs/2506.19690
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author Piecuch, Timo
Daneu, Nina
Brock, Jeffrey A.
Huang, Xiaochun
Radoševič, Tina
Müller, Arnold M.
Vockenhuber, Christof
Schneider, Christof W.
Lippert, Thomas
Shepelin, Nick A.
author_facet Piecuch, Timo
Daneu, Nina
Brock, Jeffrey A.
Huang, Xiaochun
Radoševič, Tina
Müller, Arnold M.
Vockenhuber, Christof
Schneider, Christof W.
Lippert, Thomas
Shepelin, Nick A.
contents Flexoelectricity - polarization induced by strain gradients - offers a route to polar functionality in centrosymmetric dielectrics, where traditional piezoelectric effects are absent. This study investigates the flexoelectric effect in epitaxial $\mathrm{BaHfO_3}$ (BHO) thin films, a centrosymmetric and paraelectric perovskite. While a large lattice mismatch induces defect-driven relaxation, a coherently grown BHO film undergoes elastic relaxation, forming intrinsic strain gradients exceeding $10^5\ \mathrm{m}^{-1}$. A 29-fold enhancement in spontaneous polarization is observed at an electric field of $4\ \mathrm{MV\,cm}^{-1}$ for BHO exhibiting a strain gradient compared to relaxed BHO. This enhancement is attributed to flexoelectric coupling, which is isolated from ferroelectric and piezoelectric contributions due to the centrosymmetric nature and the absence of phase transitions in BHO. The findings establish a clear link between engineered strain gradients and enhanced polarizability in oxide thin films, offering a benchmark system for deconvoluting the flexoelectric effect from other polar effects. These results provide a basis for exploiting flexoelectricity in dielectric devices and advance the fundamental understanding of strain-coupled phenomena in functional oxides.
format Preprint
id arxiv_https___arxiv_org_abs_2506_19690
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Flexoelectric Polarization Enhancement in Paraelectric $\mathrm{BaHfO_3}$ via Strain Gradient Engineering
Piecuch, Timo
Daneu, Nina
Brock, Jeffrey A.
Huang, Xiaochun
Radoševič, Tina
Müller, Arnold M.
Vockenhuber, Christof
Schneider, Christof W.
Lippert, Thomas
Shepelin, Nick A.
Materials Science
Flexoelectricity - polarization induced by strain gradients - offers a route to polar functionality in centrosymmetric dielectrics, where traditional piezoelectric effects are absent. This study investigates the flexoelectric effect in epitaxial $\mathrm{BaHfO_3}$ (BHO) thin films, a centrosymmetric and paraelectric perovskite. While a large lattice mismatch induces defect-driven relaxation, a coherently grown BHO film undergoes elastic relaxation, forming intrinsic strain gradients exceeding $10^5\ \mathrm{m}^{-1}$. A 29-fold enhancement in spontaneous polarization is observed at an electric field of $4\ \mathrm{MV\,cm}^{-1}$ for BHO exhibiting a strain gradient compared to relaxed BHO. This enhancement is attributed to flexoelectric coupling, which is isolated from ferroelectric and piezoelectric contributions due to the centrosymmetric nature and the absence of phase transitions in BHO. The findings establish a clear link between engineered strain gradients and enhanced polarizability in oxide thin films, offering a benchmark system for deconvoluting the flexoelectric effect from other polar effects. These results provide a basis for exploiting flexoelectricity in dielectric devices and advance the fundamental understanding of strain-coupled phenomena in functional oxides.
title Flexoelectric Polarization Enhancement in Paraelectric $\mathrm{BaHfO_3}$ via Strain Gradient Engineering
topic Materials Science
url https://arxiv.org/abs/2506.19690