- Award ID(s):
- 1834750
- NSF-PAR ID:
- 10315952
- Date Published:
- Journal Name:
- Inorganic Chemistry Frontiers
- Volume:
- 8
- Issue:
- 19
- ISSN:
- 2052-1553
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The hafnate perovskites PbHfO3(antiferroelectric) and SrHfO3(“potential” ferroelectric) are studied as epitaxial thin films on SrTiO3(001) substrates with the added opportunity of observing a morphotropic phase boundary (MPB) in the Pb1−
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Abstract Ferroelectric materials owning a polymorphic nanodomain structure usually exhibit colossal susceptibilities to external mechanical, electrical, and thermal stimuli, thus holding huge potential for relevant applications. Despite the success of traditional strategies by means of complex composition design, alternative simple methods such as strain engineering have been intensively sought to achieve a polymorphic nanodomain state in lead‐free, simple‐composition ferroelectric oxides in recent years. Here, a nanodomain configuration with morphed structural phases is realized in an epitaxial BaTiO3film grown on a (111)‐oriented SrTiO3substrate. Using a combination of experimental and theoretical approaches, it is revealed that a threefold rotational symmetry element enforced by the epitaxial constraint along the [111] direction of BaTiO3introduces considerable instability among intrinsic tetragonal, orthorhombic, and rhombohedral phases. Such phase degeneracy induces ultrafine ferroelectric nanodomains (1–10 nm) with low‐angle domain walls, which exhibit significantly enhanced dielectric and piezoelectric responses compared to the (001)‐oriented BaTiO3film with uniaxial ferroelectricity. Therefore, the finding highlights the important role of epitaxial symmetry in domain engineering of oxide ferroelectrics and facilitates the development of dielectric capacitors and piezoelectric devices.
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Abstract Epitaxially strained BiFeO3thin films with coexisting tetragonal‐ and rhombohedral‐like phases exhibit a range of intriguing functional properties, often strongly related to the unique microstructure of the film. Here enhancements in electromechanical response are reported during simultaneous nanoscale application of electric field and localized stress. These enhancements manifest in the form of peaks, or humps, in the piezoresponse hysteresis loops obtained under a select polarity of applied electric field, corresponding nominally to a downward polarization. Using a variation of band excitation piezoresponse force spectroscopy to collect electromechanical hysteresis loops and to simultaneously monitor the elastic behavior during switching, a comprehensive picture of the complex interplay of ferroelastic structural transitions and ferroelectric switching and its impact on the overall functional response are developed. Such an understanding is a crucial step toward realizing practical electronic devices, such as pressure sensors, incorporating this promising material.