Substitutional effect of Mg2+ on structural and magnetic properties of cobalt nanoferrite. (January 2021)

• Record Type: Journal Article
• Authors: Ounacer, M.; Essoumhi, A.; Sajieddine, M.; Razouk, A.; Fnidiki, A.; Richomme, F.; Juraszek, J.; Dubiel, S.M.; Sahlaoui, M.
• Is Part Of: Journal of physics and chemistry of solids. Volume 148(2021)
• Publication Date: 2021-01
• Subjects: Coprecipitation -- Cobalt nanoferrite -- Rietveld refinement -- Magnetism -- Mössbauer spectrometry; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2020.109687
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: This work focuses on the study of structural and magnetic properties of Mg 2+ -substituted cobalt nanoferrite (Co1 -x Mg x Fe2 O4, 0.0 ≤ x ≤ 1.0). The samples were synthesized by a coprecipitation route and then annealed at 850ؘ °C for 2 h under atmospheric air. The X-ray diffraction patterns show that the samples crystallize in a cubic spinel structure with space group F d 3 ‾ m, and 3% secondary phase was identified as hematite ( R 3 ‾ c ) for x = 1.0. The average crystallite size ( D ) and the lattice parameter were greatly influenced by Mg content ( D decreased from 38 to 20 nm). Transmission electron microscopy investigations revealed that the grains have an almost spherical shape and furthermore that the samples are chemically homogeneous. Magnetic measurements at 5 K revealed a wasp-waist magnetic hysteresis behavior of Co–Mg ferrite. The coercivity of Co0.4 Mg0.6 Fe2 O4 with D = 25 nm was enhanced, with a maximum value of 4000 Oe. The room temperature Mössbauer spectra were fitted with two Zeeman sextets, which reflects the incorporation of Fe 3+ in the A and B sublattices of the spinel structure. The hyperfine field of these sites decreases similarly to the saturation magnetization with increasing Mg content. The spectrum corresponding to x = 1.0 was calculated with the help of the hyperfine field distribution. Moreover, Mössbauer spectra, fore x = 0.0 and 1.0 were recorded at 6 and 80 K and were adjusted by the superposition of three sextets: one sextet for the A site and two sextets for the B sites (B1 and B2). The hyperfine parameters such as the hyperfine field and the isomer shift were improved at 6 and 80 K. Highlights: Mg substituted CoFe2 O4 have been synthesized by coprecipitation route and the crystallite size is ranging from 20 to 40 nm. XRD patterns reveal the formation of cubic spinel structure with lattice parameter affected by Mg content. At 5 K, a wasp-waist magnetic behavior was observed for samples with x lies between 0.2 and 0.8. Coercivity has achieved a maximum value of 4000 Oe for Co0.4 Mg0.6 Fe2 O4 sample. Mössbauer spectra highlight the influence of Mg content on hyperfine properties.