TODAY: Kalpesh Jaykar, 20-Oct-26, 12:20pm Central
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Ellad Tadmor
Oct 20, 2026, 7:22:03 AM (5 days ago) Oct 20
to aem-solid...@umn.edu
AEM Mechanics Research Seminar
Tuesday 20-Oct-2026, 12:20pm Central
Dr. Kalpesh Jaykar
Department of Aerospace Engineering and Mechanics, University of Minnesota
Title: Modeling mechanical instabilities in epitaxial barium titanate thin films
Abstract: Ferroelectric BaTiO3 (BTO) thin films are promising for electronic and photonic applications. Using Hybrid Molecular Beam Epitaxy (Hybrid MBE), high-quality epitaxial BTO films can be grown with unit-cell-level thickness control. Their behavior, however, is strongly influenced by epitaxial strain and mechanical boundary conditions arising from integration with dissimilar substrates.
In this seminar, I will present continuum theories developed to understand two distinct mechanical instabilities in epitaxial BTO thin films. In the first system, BTO films grown on a sacrificial SrO layer spontaneously roll upon release. A model incorporating polarization effects predicts the characteristic rolled-film diameter as a function of thickness and shows good agreement with experimental observations. In the second system, BTO films grown on CaSnO3/SiO2 substrates develop wrinkling patterns. Modeling the film as an orthotropic hyperelastic medium yields analytical predictions for wrinkle orientation and slope that are consistent with experimental measurements. Together, these results demonstrate how energy-minimization principles can be used to explain and predict some rolling and wrinkling instabilities in ferroelectric thin films, providing a framework for the design and control of ferroelectric heterostructures.
For more information, visit the AEM Mechanics Research Seminar website:
Tuesday 20-Oct-2026, 12:20pm Central
In-person: Room 313, Akerman Hall, University of Minnesota
Online: Webinar registration link
Department of Aerospace Engineering and Mechanics, University of Minnesota
Title: Modeling mechanical instabilities in epitaxial barium titanate thin films
Abstract: Ferroelectric BaTiO3 (BTO) thin films are promising for electronic and photonic applications. Using Hybrid Molecular Beam Epitaxy (Hybrid MBE), high-quality epitaxial BTO films can be grown with unit-cell-level thickness control. Their behavior, however, is strongly influenced by epitaxial strain and mechanical boundary conditions arising from integration with dissimilar substrates.
In this seminar, I will present continuum theories developed to understand two distinct mechanical instabilities in epitaxial BTO thin films. In the first system, BTO films grown on a sacrificial SrO layer spontaneously roll upon release. A model incorporating polarization effects predicts the characteristic rolled-film diameter as a function of thickness and shows good agreement with experimental observations. In the second system, BTO films grown on CaSnO3/SiO2 substrates develop wrinkling patterns. Modeling the film as an orthotropic hyperelastic medium yields analytical predictions for wrinkle orientation and slope that are consistent with experimental measurements. Together, these results demonstrate how energy-minimization principles can be used to explain and predict some rolling and wrinkling instabilities in ferroelectric thin films, providing a framework for the design and control of ferroelectric heterostructures.
For more information, visit the AEM Mechanics Research Seminar website:
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Ellad B. Tadmor, Ph.D.
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
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