Enhancement of magnetic and dielectric properties of KNbO3–CoFe2O4 multiferroic composites via thermal treatment

Abstract

In this work, multiferroic composites were produced from CoFe 2 O 4 and KNbO 3 mixtures via control of the heat treatment temperature. For this, CoFe 2 O 4 nanoparticles were produced by sol-gel method, while KNbO 3 was synthesized by microwave-assisted hydrothermal synthesis. The powders were homogenized and subjected to heat treatment at 300, 400 and 500 • C for 5 h. The structural, electrical and magnetic properties were characterized. The results of X-ray diffraction indicated that there was no formation of secondary phases with heat treatment. Raman vibrational modes confirmed the presence of KNbO 3 and CoFe 2 O 4 in the prepared composites. SEM analysis showed that the composite microstructure consists of smaller ferrite particles arranged on the surface of largest cubic KNbO 3 particles. The improvement of coercivity (H C = 382.1Oe) and dielectric constant (ϵ'~7860) was observed for the composite thermally treated at 300 • C. The obtained results show the potential application of KN:CFO composites for multifunctional devices.

Strain‐mediated electrical and optical properties of novel lead‐free CuFe2O4–KNbO3 nanocomposite solid solutions: A combined experimental and Density Functional Theory studies

“…Here, the appearance of the Raman mode at 194 cm −1 reflects the in situ vibration modes of NbO 6 octahedron and the mode at 280 cm −1 represents the ONbO symmetric stretching mode of NbO 6 respectively. Further, the Raman mode at 834 cm −1 is due to the symmetric stretching of NbO in NbO 4 tetrahedron (Wermuth et al, 2021). On the other hand, the pristine CuFe 2 O 4 shows five characteristic Raman active modes at 226, 293, 411, 498, and 611 cm −1 and reveal that the CuFe 2 O 4 is in the cubic spinel phase.…”

Cobalt Ferrite (CoFe2O4) Spinel as a New Efficient Magnetic Heterogeneous Fenton-like Catalyst for Wastewater Treatment

“…The Raman spectra revealed the five active Raman modes, such as T2g (3), Eg (1) and A1g (1), at 151, 311, 470, 547, and 685 cm −1 , respectively [45,46]. In the reverse spinel, the tetrahedral sites of the ferrite were occupied by half of the Fe 3+ cations, whereas the other Fe 3+ and Co 2+ cations were distributed in the octahedral sites.…”

“…The vibrational modes observed at low frequencies (~150 cm −1 to 550 cm −1 ) were attributed to the symmetry of oxygen contact with metal ions located in octahedral sites, and this can be called BO 6 . These modes represent the symmetric and antisymmetric bending of the oxygen atom with metal ions (MO) in the octahedral sites [45].…”