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ABSTRACT A systematic study of the effect of film thickness on the stability of the spin cycloid in BiFeO3grown epitaxially on TbScO3(110) substrates reveals a complex evolution of both the crystal and ferroelectric domain structures as well as the magnetic order. For films thicker than ∼5 nm, the structure remains rhombohedral, but the lattice mismatch is accommodated by the formation of 71° ferroelastic‐closure domains, rather than misfit dislocations, followed by the formation of 109° domains. For films ≲ 5 nm, a mixed‐phase coexistence of a polar, rhombohedral‐like (R3c) phase and an antipolar (Pnma) phase is observed. Scanning nitrogen‐vacancy magnetometry reveals a change in the propagation vector of the spin cycloid with thickness. It evolves from parallel to the ferroelectric domains for 50 nm thick samples and thicker and reorients to perpendicular to the ferroelectric domains for intermediate thicknesses, and vanishes for films ≲ 5 nm, which is reflected in macroscopic spin transport measurements and supported by the simulations. Ultimately, this work provides a deep understanding of the role of film thickness and electrostatic boundary conditions on the ferroelectric domain configuration and, therefore on the spin cycloid to design the device with electric field control antiferromagnetism.
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In situ determination of the interplay of the structure and domain under a subcoercive field in BiScO 3 –PbTiO 3
The extraordinary performances of phase-coexisting ferroelectrics are significantly affected by not only the phase constitution but also the motion of domain walls. The study on the role of phase coexistence in the formation of ferroelectric and ferroelastic domain microstructures is of great importance to explain the enhanced piezoelectric properties. In situ high-energy diffraction and the Rayleigh law are utilized to reveal the interplay of phase constitution and domain configuration to the macroscopic electromechanical coupling effect in the morphotropic phase boundary composition of 0.365BiScO 3 –0.635PbTiO 3 during the application of a weak electrical loading in the present study. It was found that anisotropic phase transition and domain switching occur in polycrystalline ferroelectric ceramics and a phase transition occurs dramatically beyond the coercive field. Taking into account the important role of coupled ferroelectric and ferroelastic domain microstructures, we conceived a configuration of monoclinic domains coexisting with and bridging the tetragonal domains. The existence of bridging domains would provide an insight into the interplay of the phase and domain and explains the piezoelectric performance in the vicinity of morphotropic phase boundaries.
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- Award ID(s):
- 1834750
- 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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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1039/d1qi00670c
