Rietveld refined structural and sintering temperature dependent electromagnetic properties of Al3+ substituted Ni–Co ferrites prepared through sol–gel auto combustion method for high-frequency and microwave devices

• Published in: Journal of materials science. Materials in electronics 2024-05, Vol.35 (14), p.952, Article 952
• Main Authors: Rahman, M. M., Ullah, M. Hedayet, Tabassum, S., Hoque, M. A., Harun-Or-Rashid, M.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Coercivity; Combustion; Crystallites; Electromagnetic properties; Ferrimagnetic materials; Ferrites; Homogeneity; Magnetic moments; Magnetic properties; Magnetic saturation; Materials Science; Microwave equipment; Nanoparticles; Optical and Electronic Materials; Sintering (powder metallurgy); Sol-gel processes; Spinel; Spintronics; Temperature dependence
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-12632-2

This research focuses on the formation and assessment of sol–gel auto-combustion-produced nanocrystalline Co 0.40 Ni 0.6 Al x Fe 2−x O 4 (x = 0.00, 0.05, 0.1, 0.2) ferrites. The investigation explores the structural, morphological, electrical, dielectric, and magnetic characteristics of the spinel ferrites sintered at different temperatures (850 °C and 950 °C), with a specific emphasis on the impact of Al 3+ substitution. A cubic single-phase spinel structure exhibiting excellent crystallinity and homogeneity is found across all samples, based on XRD evaluation. The nanoparticles had typical crystallite sizes between 40 and 48 nm and average particle sizes between 122 and 186 nm. Increasing Al 3+ content resulted in increased nanoparticle porosity. According to infrared spectroscopy, the adsorption band v 1 rose from 538 to 554 cm −1 whereas the v 2 band dropped from 374 to 366 cm −1 . With an increase in Al 3+ content, the experimental magnetic moment ( η exp ) and saturation magnetization ( M s ) of the nanoparticles showed a notable upward trend. Furthermore, the samples sintered at 950 °C displayed higher AC resistivity, attributed to a reduction of the hopping electron within the grains. All of the ferrite nanoparticles under investigation also showed high coercivity values (1028.32–1222.76 Oe), designating them as ferrimagnetic materials and emphasizing the possibility for use in spintronics, high-frequency and microwave equipment like radar, antenna, and so on.