Incorporation of Mn2+ into cobalt ferrite via sol–gel method: insights on induced changes in the structural, thermal, dielectric, and magnetic properties

• Published in: Journal of sol-gel science and technology Vol. 90; no. 3; pp. 631 - 642
• Main Authors: Abdel Maksoud, M. I. A., El-ghandour, Ahmed, El-Sayyad, Gharieb S., Awed, A. S., Ashour, A. H., El-Batal, Ahmed I., Gobara, Mohamed, Abdel-Khalek, E. K., El-Okr, M. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-06-2019; Springer Nature B.V
• Subjects: Ceramics; Chemistry and Materials Science; Cobalt ferrites; Composites; Crystal structure; Dielectric loss; Dielectric properties; Dislocations; Electrochemical impedance spectroscopy; Electron microscopes; electronic; Fourier transforms; Glass; Infrared spectroscopy; Inorganic Chemistry; magnetic and ferroelectric applications; Magnetic properties; Manganese ions; Materials Science; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Sol-gel and hybrid materials for dielectric; Photomicrographs; Porosity; Scanning electron microscopy; Sol-gel processes; Spectrum analysis; Stoichiometry; Synthesis; Thermogravimetric analysis; Torquemeters; Transmission electron microscopy; Weight loss; X-ray diffraction; SEM micrographs; Magnetization; Sol–gel; TEM; Manganese-cobalt ferrite
• DOI: 10.1007/s10971-019-04964-x
• EISSN: 1573-4846
• ISSN: 0928-0707

Precise tailoring of nanostructured cobalt ferrite paves the way to design and develop devices for stress and noncontact torque sensors. Herein, Mn
2+
ions are inserted into cobalt ferrite with different ratios using a facile sol–gel method. The as-synthesized ferrites are characterized via energy dispersive X-ray (EDX), Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), thermogravimetric analysis (TGA), electrochemical impedance spectroscopy (EIS), and vibrating sample magnetometer (VSM). EDX analyses affirm the stoichiometry of the synthesized samples with the intended ratios. The FTIR and XRD prove the presence of a single-phase cubic spinel structure for all as-synthesized samples. The dislocation, the inter-chain distance and the distortion parameter values decrease with increasing Mn
2+
content, which outweigh the improvement of the crystal structure of the doped CFO samples. SEM micrographs illustrate that the incorporation of Mn
2+
significantly soars the porosity of the samples. TEM images reveal that the samples comprise particles in the nanometer range with spherical shape and porous nature. Thermal analyses show that the weight loss is dependent on Mn
2+
content in the sample. For instance, at
x
 = 0, a slight variation in the weight loss estimated by 8% is observed while at
x
 = 0.25 the weight loss has reached up to 40%. The dielectric losses (8 × 10
5
) of Co
0.5
Mn
0.5
Fe
2
O
4
is enough to meet the demands of microwave applications. Finally, a reduction in the magnetization of the pure CFO from 68.419 emu g
−1
to 50.307 emu g
−1
is achieved at
x
 = 0.25.
Herein, manganese substituted cobalt ferrites were synthesized using a facile sol–gel method. The Rietveld refinements of Co
1-x
Mn
x
Fe
2
O
4
have studied. SEM images have indicated that the surface of the as-synthesized NPs has some porous shapes. EDX analyses have affirmed the stoichiometry of the samples. The TEM image reveals that particles are in the nanometer range. Thermal analyses show that the weight loss is dependent on Mn
2+
content in the sample. The dielectric losses (8 × 10
5
) of Co
0.5
Mn
0.5
Fe
2
O
4
is enough to meet the demands of microwave applications. The hysteresis loops reveal that the magnetic behavior of the CFO NPs is significantly influenced by Mn
2+
ions substitution.
Highlights
Mn
2
+ is successfully incorporated into cobalt ferrite (CoFe
2
O
4
) via sol–gel method.
XRD and Williamson-Hall analyses reveal that all samples comprise nanoparticles.
SEM micrographs show that the samples’ porosity soars with increasing Mn
2+
content.
TEM images reveal that the samples consist of spherical nanoparticle porous nature.
The sample of the highest content of Mn
2+
has the lowest Gibbs energy.