Browsing by Author "Kuo, H. Y."

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Domain pattern and piezoelectric response across polymorphic phase transition in strained bismuth ferrite films
(2010-12-13)
Kuo, H. Y.
;
Shu, Y. C.
;
Chen, H. Z.
;
Hsueh, C. J.
;
Wang, C. H.
A model is developed to investigate the domain pattern and piezoelectric response across the polymorphic phase transition in strained epitaxial bismuth ferrite films. The orientations of stripelike pattern of the mixed rhombohedral and tetragonal phases are predicted as the consequence of competition between elastic and depolarization energies. The abnormally large piezoelectric response is attributed to the strain-driven softening in dielectric stiffness. The results are in good agreement with recent experimental observations and provide a guidance for developing similar strain-driven polymorphic phase transition in other related perovskite material systems. (C) 2010 American Institute of Physics. [doi:10.1063/1.3525926]
Effect of imperfect interfaces on the field response of multilayered magneto-electroelastic composites under surface loading
(2019-11-01)
Kuo, H. Y.
;
Huang, C. S.
;
Pan, E.
;
土木工程學系
;
Department of Civil Engineering
Layered magneto-electro-elastic (MEE) composites with imperfect interface have been investigated in recent years for enhancing the important magnetoelectric coupling effect. However, the impact of the imperfect interface on the elastic, electric and magnetic behaviors has not been studied in details so far. In this paper, a simply supported and multilayered MEE plate with one of the typical imperfect interfaces is proposed to deeply understand the response of the layered plate under surface loading, which mimics the simple tests used in experiments. Based on the extended pseud Stroh formalism and the dual variable and position method, the analytical solutions for anisotropic and multilayered MEE plates with imperfect interfaces are derived. In our numerical studies, we choose BaTiO3 (BTO) as the piezoelectric phase and CoFe2O4 (CFO) as the piezomagnetic phase to construct two sandwich plates (BTO/CFO/BTO, and CFO/BTO/CFO). Under surface loading, responses of these two sandwich plates are analyzed which demonstrate the possibility of optimal tuning the elastic, electric and magnetic fields.
Enhancing magnetoelectric effect in magneto-electro-elastic laminated composites via interface modulus and stress
(2020-06-15)
Kuo, H. Y.
;
Shih, C. L.
;
Pan, E.
;
土木工程學系
;
Department of Civil Engineering
Magnetoelectric (ME) coupling is of interest for a variety of applications, but it is weak in a single-phase material. Strain-coupled laminates are an efficient way to achieve a high ME coupling. In this paper, we first derive an exact solution for a simply supported multilayered anisotropic magneto-electro-elastic plate with interfacial magneto-electro-elasticity. It is expressed in terms of the extended pseudo Stroh formalism along with the propagator matrix method. The interface modulus and stress are considered by constructing an interface matrix. Based on this solution, sandwich plates made of different layups of piezoelectric and piezomagnetic materials are numerically studied. Our results indicate that for the given layup, it is possible to tune the ME coupling by the interface modulus and stress. Considering interface effect is common in nanoplate, this study could provide an extra channel for turning the ME coupling in the layered magneto-electro-elastic plates with possible device applications. (C) 2020 Elsevier Ltd. All rights reserved.
Investigation of nanodomain pattern and piezoelectric behavior of mixed phases in epitaxial BiFeO(3) films
(2011-12-01)
Kuo, H. Y.
;
Shu, Y. C.
;
Chen, H. Z.
;
Hsueh, C. J.
;
Wang, C. H.
Mixed phases of rhombohedral and tetragonal ferroelectric variants have been recently observed to coexist through epitaxial constraints in bismuth ferrite films. They form stripe-like domain patterns with orientations closely parallel to the substrate edges and exhibit unusually large piezoelectric response in the stripe areas. Here a model is developed for explaining the peculiar domain orientations as well as the enhancement of piezoelectricity in the mixed phase. The former is determined by the relative magnitudes of elastic and depolarization energy, whereas the latter is ascribed to the strain-driven softening in dielectric stiffness. The predictions show the similar trend as those observed in recent experiments. (C) 2011 Elsevier Ltd. All rights reserved.
Investigation of nanodomain pattern and piezoelectric behavior of mixed phases in epitaxial BiFeO3 films
(2011-12-01)
Kuo, H. Y.
;
Shu, Y. C.
;
Chen, H. Z.
;
Hsueh, C. J.
;
Wang, C. H.
Mixed phases of rhombohedral and tetragonal ferroelectric variants have been recently observed to coexist through epitaxial constraints in bismuth ferrite films. They form stripe-like domain patterns with orientations closely parallel to the substrate edges and exhibit unusually large piezoelectric response in the stripe areas. Here a model is developed for explaining the peculiar domain orientations as well as the enhancement of piezoelectricity in the mixed phase. The former is determined by the relative magnitudes of elastic and depolarization energy, whereas the latter is ascribed to the strain-driven softening in dielectric stiffness. The predictions show the similar trend as those observed in recent experiments. (C) 2011 Elsevier Ltd. All rights reserved.