Excess of cations in the sol-gel synthesis of cobalt ferrite (CoFe2O4): A pathway to switching the inversion degree of spinels

Venturini, Janio; Tonelli, Amanda Mallmann; Wermuth, Tiago Bender; Zampiva, Rúbia Young Sun; Arcaro, Sabrina; Viegas, A.D.C.; Bergmann, Carlos Pérez

doi:10.1016/j.jmmm.2019.03.057

Cited by 66 publications

(16 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The development of new functional composites with controllable magnetic and microwave properties is one of the important tasks of modern applied physics. Nowadays, functional hard-soft magnetic composites are attracting the attention of scientists; spinel ferrites and composites based on them have had great contributions in many fields, such as materials for catalysis [1,2], targeted drug delivery [3], microwave, gas sensors [4], magneto-optical data storage [5], medicines, cancer treatment, telecommunications, photoactive materials, and photo-catalysts. Microwave absorption is one of the most promising directions of complex iron oxides [6,7] because its high saturation magnetization (M s ), large coercivity (H c ), and strong coupling between magnetic phases.…”

Section: Introductionmentioning

confidence: 99%

Functional Sr0.5Ba0.5Sm0.02Fe11.98O4/x(Ni0.8Zn0.2Fe2O4) Hard–Soft Ferrite Nanocomposites: Structure, Magnetic and Microwave Properties

et al. 2020

View full text Add to dashboard Cite

This paper reports the correlation between the composition of the functional Sr0.5Ba0.5Sm0.02Fe11.98O19/x(Ni0.8Zn0.2Fe2O4) hard–soft nanocomposites (SrBaSmFe/x(NiZnFe) NCs), where 0.0 ≤ x ≤ 3.0, and their structural features, magnetic, and microwave properties. SrBaSmFe/x(NiZnFe) hard/soft ferrite NCs are produced using the one-pot citrate combustion method. According to the XRD analysis, all samples showed the co-existence of both SrBaSmFe and NiZnFe phases in different ratios. Magnetic properties are measured in a wide range of magnetic fields and temperatures (10 and 300 K) and correlated well with the composition of the investigated samples. The microwave properties (frequency dispersions of the magnetic permeability, and electrical permittivity) are discussed by using the co-axial method in the frequency range of 0.7–18 GHz. Non-linear dependences of the main microwave features were observed with varying of composition. The microwave behavior correlated well with the composite theory. These results could be used in practice for developing antenna materials.

show abstract

Section: Introductionmentioning

confidence: 99%

Functional Sr0.5Ba0.5Sm0.02Fe11.98O4/x(Ni0.8Zn0.2Fe2O4) Hard–Soft Ferrite Nanocomposites: Structure, Magnetic and Microwave Properties

et al. 2020

View full text Add to dashboard Cite

show abstract

“…In order to tailor the reactivity and catalytic properties of cobalt ferrites and to decorrelate the different influence on these properties, nano ferrites with different shapes, ie nanooctahedron [31,32] and nanocubes (this work) were synthesized. Cobalt ferrites are mixed ferrites, with an inversion degree that varies with the cobalt amount, particle size, and the synthesis method [33][34][35][36], so the cation distribution, about the tetrahedral and octahedral sites, should also be taken into account when discussing cobalt ferrites properties [21].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of CoFe2O4 nanocubes

Medeiros

Madigou

Moriyama

et al. 2020

Nano-Structures & Nano-Objects

View full text Add to dashboard Cite

“…This corresponds to a magnetic moment per formula unit of M s = 3.65 μ B /fu and it is expected to characterize the situation when the moments of both core and shell are oriented along the same axis. Thus, the inversion factor can be determined from saturation magnetization [ 24 , 25 ] as being x = (1/4)(7− M s ) = 0.838. The composition of the sample (Co 0.162 Fe 0.838 ) T (Co 0.838 Fe 1.162 ) O O 4 is closer to that of an inverse-spinel-type structure.…”

Section: Resultsmentioning

confidence: 99%

New Insights into the Magnetic Properties of CoFe2O4@SiO2@Au Magnetoplasmonic Nanoparticles

et al. 2022

View full text Add to dashboard Cite

We report the successful synthesis and a complete magnetic characterization of CoFe2O4@SiO2@Au magnetoplasmonic nanoparticles. The CoFe2O4 magnetic nanoparticles were prepared using the hydrothermal method. A subsequent SiO2 shell followed by a plasmonic Au shell were deposited on the magnetic core creating magnetoplasmonic nanoparticles with a core–shell architecture. A spin-glass-type magnetism was shown at the surface of the CoFe2O4 nanograins. Depending on the external magnetic field, two types of spin-glass were identified and analyzed in correlation with the exchange field acting on octahedral and tetrahedral iron sites. The magnetization per formula unit of the CoFe2O4 core is not changed in the case of CoFe2O4@SiO2@Au nanocomposites. The gold nanoparticles creating the plasmonic shell show a giant diamagnetic susceptibility, dependent on their crystallite sizes.

show abstract

Excess of cations in the sol-gel synthesis of cobalt ferrite (CoFe2O4): A pathway to switching the inversion degree of spinels

Cited by 66 publications

References 50 publications

Functional Sr0.5Ba0.5Sm0.02Fe11.98O4/x(Ni0.8Zn0.2Fe2O4) Hard–Soft Ferrite Nanocomposites: Structure, Magnetic and Microwave Properties

Functional Sr0.5Ba0.5Sm0.02Fe11.98O4/x(Ni0.8Zn0.2Fe2O4) Hard–Soft Ferrite Nanocomposites: Structure, Magnetic and Microwave Properties

Synthesis of CoFe2O4 nanocubes

New Insights into the Magnetic Properties of CoFe2O4@SiO2@Au Magnetoplasmonic Nanoparticles

Contact Info

Product

Resources

About