Tailoring structural, electrical, and magnetoelectric properties of BiFeO3 ceramics via low-level cobalt substitution
(2026) In Journal of Alloys and Compounds 1055.- Abstract
This study presents a comprehensive investigation of the structural, microstructural, electrical, magnetic, and magnetoelectric properties of low-level substitution of Co3 + for Fe3+ ions in the perovskite B-site of BiFeO3 (BiFe1−xCoxO3, x = 0.01, 0.015 and 0.02). X-ray diffraction combined with Rietveld refinement confirms the retention of the rhombohedral R3c structure across all compositions, with a systematic contraction of the lattice parameters attributed to the smaller ionic radius of Co3+ compared to Fe3+. Microstructural analysis revealaled a doping-induced evolution from heterogeneous grain growth and high microstrain at intermediate doping... (More)
This study presents a comprehensive investigation of the structural, microstructural, electrical, magnetic, and magnetoelectric properties of low-level substitution of Co3 + for Fe3+ ions in the perovskite B-site of BiFeO3 (BiFe1−xCoxO3, x = 0.01, 0.015 and 0.02). X-ray diffraction combined with Rietveld refinement confirms the retention of the rhombohedral R3c structure across all compositions, with a systematic contraction of the lattice parameters attributed to the smaller ionic radius of Co3+ compared to Fe3+. Microstructural analysis revealaled a doping-induced evolution from heterogeneous grain growth and high microstrain at intermediate doping levels to a more refined and compact microstructure at 2.0 at%, suggesting the presence of stress relaxation mechanisms. Electrical measurements demonstrated that cobalt doping significantly modulated resistivity and time stability, with the 2.0 at% sample exhibiting enhanced stability and lower resistivity due to improved charge transport pathways. Dielectric analysis indicates a trade-off between permittivity and losses: while low doping favors dielectric stability with minimal conduction losses, higher cobalt content enhances permittivity at the expense of increased dielectric losses driven by defect-mediated hopping conduction. Magnetic characterization reveals a progressive collapse of the cycloidal spin structure, resulting in enhanced remanent magnetization, coercivity, Rayleigh nonlinearity, and magnetic energy dissipation. Magnetoelectric coupling exhibited a strong dependence on doping levels, with robust intrinsic coupling at x = 0.01 transitioning to defect-driven extrinsic behavior at higher concentrations. Notably, the strongest and most symmetric magnetoelectric response is observed at x = 0.01, indicating that low-level Co substitution is sufficient to suppress the cycloidal spin structure while preserving high electrical resistivity and intrinsic coupling mechanisms. Higher Co concentrations, although enhancing magnetic irreversibility, introduce defect-driven conduction and extrinsic effects that deteriorate the magnetoelectric performance. These findings establish cobalt substitution as an effective strategy for tailoring the multifunctional properties of BiFeO3, providing key insights into the interplay between structural distortions, defect chemistry, and functional performance in multiferroic perovskite systems.
(Less)
- author
- Mincache, Anuar José LU ; Mantovani, Ana Carolina ; Colombo, Gabriel Tolardo ; da Silva Tupan, Lilian Felipe ; Dias, Gustavo Sanguino ; dos Santos, Ivair Aparecido and Cotica, Luiz Fernando
- organization
- publishing date
- 2026-02
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- BiFeO3 ceramics, Cobalt doping, Magnetoelectric coupling, Multiferroic properties
- in
- Journal of Alloys and Compounds
- volume
- 1055
- article number
- 186070
- publisher
- Elsevier
- external identifiers
-
- scopus:105029037258
- ISSN
- 0925-8388
- DOI
- 10.1016/j.jallcom.2026.186070
- language
- English
- LU publication?
- yes
- id
- 01fdc0ee-b976-423e-a6ab-f1e7236ee376
- date added to LUP
- 2026-02-18 14:40:31
- date last changed
- 2026-02-18 14:40:52
@article{01fdc0ee-b976-423e-a6ab-f1e7236ee376,
abstract = {{<p>This study presents a comprehensive investigation of the structural, microstructural, electrical, magnetic, and magnetoelectric properties of low-level substitution of Co<sup>3 +</sup> for Fe<sup>3+</sup> ions in the perovskite B-site of BiFeO<sub>3</sub> (BiFe<sub>1−x</sub>Co<sub>x</sub>O<sub>3</sub>, x = 0.01, 0.015 and 0.02). X-ray diffraction combined with Rietveld refinement confirms the retention of the rhombohedral R3c structure across all compositions, with a systematic contraction of the lattice parameters attributed to the smaller ionic radius of Co<sup>3+</sup> compared to Fe<sup>3+</sup>. Microstructural analysis revealaled a doping-induced evolution from heterogeneous grain growth and high microstrain at intermediate doping levels to a more refined and compact microstructure at 2.0 at%, suggesting the presence of stress relaxation mechanisms. Electrical measurements demonstrated that cobalt doping significantly modulated resistivity and time stability, with the 2.0 at% sample exhibiting enhanced stability and lower resistivity due to improved charge transport pathways. Dielectric analysis indicates a trade-off between permittivity and losses: while low doping favors dielectric stability with minimal conduction losses, higher cobalt content enhances permittivity at the expense of increased dielectric losses driven by defect-mediated hopping conduction. Magnetic characterization reveals a progressive collapse of the cycloidal spin structure, resulting in enhanced remanent magnetization, coercivity, Rayleigh nonlinearity, and magnetic energy dissipation. Magnetoelectric coupling exhibited a strong dependence on doping levels, with robust intrinsic coupling at x = 0.01 transitioning to defect-driven extrinsic behavior at higher concentrations. Notably, the strongest and most symmetric magnetoelectric response is observed at x = 0.01, indicating that low-level Co substitution is sufficient to suppress the cycloidal spin structure while preserving high electrical resistivity and intrinsic coupling mechanisms. Higher Co concentrations, although enhancing magnetic irreversibility, introduce defect-driven conduction and extrinsic effects that deteriorate the magnetoelectric performance. These findings establish cobalt substitution as an effective strategy for tailoring the multifunctional properties of BiFeO<sub>3</sub>, providing key insights into the interplay between structural distortions, defect chemistry, and functional performance in multiferroic perovskite systems.</p>}},
author = {{Mincache, Anuar José and Mantovani, Ana Carolina and Colombo, Gabriel Tolardo and da Silva Tupan, Lilian Felipe and Dias, Gustavo Sanguino and dos Santos, Ivair Aparecido and Cotica, Luiz Fernando}},
issn = {{0925-8388}},
keywords = {{BiFeO3 ceramics; Cobalt doping; Magnetoelectric coupling; Multiferroic properties}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Journal of Alloys and Compounds}},
title = {{Tailoring structural, electrical, and magnetoelectric properties of BiFeO<sub>3</sub> ceramics via low-level cobalt substitution}},
url = {{http://dx.doi.org/10.1016/j.jallcom.2026.186070}},
doi = {{10.1016/j.jallcom.2026.186070}},
volume = {{1055}},
year = {{2026}},
}