Improved wideband electromagnetic performance in La3+ substituted Mn–Zn spinel ferrites: structure–microstructure regulation of grain-boundary non-Debye relaxation
- 1Solid State Physics Laboratory, Dept. of Physics, Khulna University of Engineering & Technology Khulna-9203 Bangladesh
Abstract
Grain-boundary related electrical relaxation and microstructural evolution are important factors in the frequency-dependent response of Mn–Zn ferrite. Here, La3+ substituted Mn–Zn ferrites, were synthesized by a solid-state route (calcination at 800 °C for 4 h and sintering at 1200 °C for 6 h). Rietveld refinement confirms a spinel-dominant cubic phase for all compositions. A minor orthorhombic phase appears above a La3+ threshold and remains below about 4%. The lattice parameter shows only small variation (about 8.41–8.45 Å). SEM and density analysis show grain refinement from about 1.87 µm to 1.07 µm and a non-monotonic porosity evolution (about 16–36%). Room-temperature hysteresis loops confirm soft magnetic behavior. The saturation magnetization increases strongly and reaches 33.96 emu g−1 at an intermediate La3+ level. Wideband measurements show composition-dependent relatively stable real permeability and strongly reduced magnetic loss at high frequency. Dielectric and impedance spectra show strong low-frequency dispersion consistent with Maxwell–Wagner interfacial polarization. Electric modulus and Cole–Cole plots exhibit depressed arcs, indicating non-Debye relaxation with distributed relaxation times dominated by grain boundaries. Nyquist fitting separates grain and grain-boundary responses and shows composition-tunable interfacial barrier behavior. Overall, the results demonstrate that La3+ substitution modifies the structural and microstructural state of Mn–Zn ferrites, establishing a composition-dependent balance between magnetic properties, interfacial relaxation, and high-frequency electromagnetic response.
Related
- Microcapacitor-Network-Enabled multiple relaxation in ultrathin ferroelectric ceramics for high-performance electromagnetic absorption and intelligent sensing
- Electronic and Steric Effects on the Photoswitching and Thermal Relaxation of Ortho-Substituted Pyrazole Azo Phthalimides
- Synergistic Polarization Relaxation Loss in Multimetallic Hierarchical Hybridization and Preferred Orientation Strategies for Electromagnetic Wave Absorption
- Enabling the High-Volume Utilization of Iron-Rich Sewage Sludge Ash in Cement: The Role of Curing Temperature in Microstructure and Performance Enhancement
- Synthesis, characterization, and catalytic performance of cobalt and nickel-substituted polyoxometalates organic-inorganic nanohybrids
BibTeX
@article{munna2026improved,
title = {{Improved wideband electromagnetic performance in La3+ substituted Mn–Zn spinel ferrites: structure–microstructure regulation of grain-boundary non-Debye relaxation}},
author = {Sabbir Hasan Munna and Kazi Afsana Rahman and Md. Alamgir Hossain},
journal = {RSC Advances},
year = {2026},
month = nov,
doi = {10.1039/d6ra09155e},
url = {https://doi.org/10.1039/d6ra09155e},
note = {CC BY 3.0},
}
RIS
TY - JOUR
TI - Improved wideband electromagnetic performance in La3+ substituted Mn–Zn spinel ferrites: structure–microstructure regulation of grain-boundary non-Debye relaxation
AU - Sabbir Hasan Munna
AU - Kazi Afsana Rahman
AU - Md. Alamgir Hossain
PY - 2026
DA - 2026/11/05
JO - RSC Advances
DO - 10.1039/d6ra09155e
UR - https://doi.org/10.1039/d6ra09155e
AB - Grain-boundary related electrical relaxation and microstructural evolution are important factors in the frequency-dependent response of Mn–Zn ferrite. Here, La3+ substituted Mn–Zn ferrites, were synthesized by a solid-state route (calcination at 800 °C for 4 h and sintering at 1200 °C for 6 h). Rietveld refinement confirms a spinel-dominant cubic phase for all compositions. A minor orthorhombic phase appears above a La3+ threshold and remains below about 4%. The lattice parameter shows only small variation (about 8.41–8.45 Å). SEM and density analysis show grain refinement from about 1.87 µm to 1.07 µm and a non-monotonic porosity evolution (about 16–36%). Room-temperature hysteresis loops confirm soft magnetic behavior. The saturation magnetization increases strongly and reaches 33.96 emu g−1 at an intermediate La3+ level. Wideband measurements show composition-dependent relatively stable real permeability and strongly reduced magnetic loss at high frequency. Dielectric and impedance spectra show strong low-frequency dispersion consistent with Maxwell–Wagner interfacial polarization. Electric modulus and Cole–Cole plots exhibit depressed arcs, indicating non-Debye relaxation with distributed relaxation times dominated by grain boundaries. Nyquist fitting separates grain and grain-boundary responses and shows composition-tunable interfacial barrier behavior. Overall, the results demonstrate that La3+ substitution modifies the structural and microstructural state of Mn–Zn ferrites, establishing a composition-dependent balance between magnetic properties, interfacial relaxation, and high-frequency electromagnetic response.
SN - 2046-2069
ER -