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Abstract The switching characteristics of ferroelectrics and multiferroics are influenced by the interaction of topological defects with domain walls. We report on the pinning of polarization due to antiphase boundaries in thin films of the multiferroic hexagonal YbFeO3. We have directly resolved the atomic structure of a sharp antiphase boundary (APB) in YbFeO3thin films using a combination of aberration-corrected scanning transmission electron microscopy (STEM) and total energy calculations based on density-functional theory (DFT). We find the presence of a layer of FeO6octahedra at the APB that bridges the adjacent domains. STEM imaging shows a reversal in the direction of polarization on moving across the APB, which DFT calculations confirm is structural in nature as the polarization reversal reduces the distortion of the FeO6octahedral layer at the APB. Such APBs in hexagonal perovskites are expected to serve as domain-wall pinning sites and hinder ferroelectric switching of the domains.
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Manifestation of chemical pressure: Magnetism and magnetostriction in nanoscale RFeO 3 (R = Sm, Dy, Ho, and Lu)
Abstract The effect of ionic radii sizes on magnetostriction is studied in relation to structural and magnetic properties. To explore the effect of the chemical pressure, nanoparticles of rare‐earth (RE) orthoferrites, SmFeO3, DyFeO3, HoFeO3, and LuFeO3are studied using X‐ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. Magnetic and magnetostriction measurements are also performed. In these orthoferrites, the coordination of the RE ion is eightfold, whereas the RE ionic radii are significantly different, which directly influences the structural parameters. The distortion of FeO6octahedra is observed as a result of changing chemical pressure within the lattice. The different magnitudes of magnetostriction in RE orthoferrites can be attributed to the different degrees of distortion of FeO6octahedra, R–O dynamics, and spin–orbit interactions in the system. The maximum value of magnetostriction (∼ 19 ppm) and magnetization at 2 K (30.64 emu/g) is demonstrated by HoFeO3. Comparison of structural parameters of the samples to their respective bulk counterparts indicated relative structural distortion in nanoparticles.
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- PAR ID:
- 10486735
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 107
- Issue:
- 5
- ISSN:
- 0002-7820
- Format(s):
- Medium: X Size: p. 3368-3379
- Size(s):
- p. 3368-3379
- Sponsoring Org:
- National Science Foundation
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