Spinel Ferrites (CoFe2O4): Synthesis, Magnetic Properties, and Electromagnetic Generator for Vibration Energy Harvesting

Towards hard-magnetic behavior of CoFe2O4 nanoparticles: a detailed study of crystalline and electronic structures, and magnetic properties

“…It is worth noticing that the intensity ratio between two modes of 617 cm −1 (A 1g (2) associated with Co at the tetrahedral site) and 475 cm −1 (T 2g (2), associated with Co at the octahedral site 14 ) also varies versus t m , similar to the comparison of the intensity ratio between 617 cm −1 (A 1g (2)) and 686 cm −1 (A 1g (1)) mentioned above. These features reect the migration of Co and Fe ions between the tetrahedral (A) and octahedral (B) sites as varying t m .…”

“…41,43 It should be noticed that as studying Fe 3 O 4 , at frequencies above 600 cm −1 , it is only observed one mode due to A 1g . 44,45 The A 1gband splitting into two sub-bands A 1g (1) and A 1g (2) in CoFe 2 O 4 hints that 686 cm −1 (A 1g (1)) and 617 cm −1 (A 1g (2)) are related to FeO 4 and CoO 4 tetrahedra, respectively. 41,46 One can thus rely upon their intensity ratio (A 1g (1)/A 1g (2)) to assess the cation distribution at the A and B sites.…”

“…6. Basically, 617 cm −1 (A 1g (2)) and 686 cm −1 (A 1g (1)) are associated with symmetric stretching of O atoms versus Co and/or Fe atoms in the tetrahedral (AO 4 ) sites. 41,43 It should be noticed that as studying Fe 3 O 4 , at frequencies above 600 cm −1 , it is only observed one mode due to A 1g .…”

“…Spinel-type ferrite oxides are important materials used widely in many technological applications, including permanent magnets, high-density data storage, rechargeable lithium-ion batteries, microwave absorbers, electromagnetic generators, aqueous supercapacitors, and biomedical labeling. [1][2][3][4][5] Their chemical formula is generalized as AB 2 O 4 , where A and B are usually divalent and trivalent cations, respectively. They crystallize in a cubic lattice, and belong to the Fd 3m space group.…”

Synthesis and application of mixed-spinel magnesioferrite: structural, vibrational, magnetic, and electrochemical sensing properties

“…Due to their intricate structures with the presence of cations with multiple oxidation states, and tunable magnetic and electronic properties, spinels find potential applications in spintronics, new-generation electronics, energy conversion, catalysis, and sensor technologies. [11][12][13][14][15][16] The spinel ferrites have superior properties such as a higher surface area and porosity in their structure. They are reported to act as electrode-modifying materials because they mediate electrontransfer reactions of electroactive species in solution.…”