Metal-semiconductor transition and Seebeck inversion in CoFe 2 O 4 nanoparticles

CoFe2O4 Nanomaterials: Effect of Annealing Temperature on Characterization, Magnetic, Photocatalytic, and Photo-Fenton Properties

“…Different XRD patterns of cobalt ferrites corresponding to different annealing temperatures are shown in Figure 1. The reflection peaks corresponded to the characteristic spacing between (220), (311), (400), (511), and (440) plans of a cubic spinel structure, providing clear evidence of the formation of cobalt ferrite (JCPDS number 22-1086) [5]. α-Fe2O3 peaks corresponding to secondary impurities were observed for the sample annealed at 800 °C, which was possibly caused by sample decomposition [38].…”

“…To alter structure and magnetic properties of ferrite nanoparticles, it is necessary to modify their composition and microstructures via different preparation routes [2]. CoFe 2 O 4 nanoparticles were previously prepared by a wide array of synthesis routines, such as 2 of 14 sol-gel [3,4], hydrothermal method [5], chemical co-precipitation [6,7], solvothermal [8], solid-state method [9], and solution combustion [10][11][12][13]. For each synthesis method, it was found that the annealed temperature played a key role in determining the structure and properties of the obtained product.…”

Thermal stability, electrochemical and structural characterization of hydrothermally synthesised cobalt ferrite (CoFe2O4)

“…CoFe 2 O 4 , which are in the range between 0.55 to 0.65 eV. 57,58,62,63 Furthermore, it reveals that hole hopping between the Co sites is the dominant transport mechanism at low temperatures as the activation energy for electron hopping between Fe sites is in the range of 0.2 eV. [57][58][59] For the CFO@400 pellet the same activation energy was determined.…”

“…As the electron mobility is larger than the hole mobility, the overall transport behavior at high temperatures is dominated by the electronic conductivity resulting in the observed decrease of the activation energy in agreement with previous reports. 62,63 Experimental Chemicals Tetraethylammonium hydroxide (20% w/w in water) (TENOH) and sodium hydroxide were purchased from Sigma Aldrich (Milan, Italy). Iron(III) nitrate nonahydrate was purchased from Merck (Darmstadt, Germany).…”

The Effect of Mg<sup>2+</sup> Substitution with Li<sup>1+</sup> on Structural and Optical Properties of Zn<sub>0.5</sub>Li<sub>2x</sub>Mg<sub>0.5-x</sub> Fe<sub>2</sub>O<sub>4</sub> Nanoparticles

“…Ferrites nanoparticles are used widely in high-frequency applications [6]. however the Nanoferrite materials are found to use in different physical, chemical and medicine fields, such as semiconductor CoFe 2 O 4 nanoparticles [7], ZnFe 2 O 4 , NiFe 2 O 4 in solar cell [8], magnetic resonance MnFe 2 O 4 [9], microwave Cd x Co 1-x Fe 2 O 4 (x = 0.0, 0.2, 0.35, 0.5) [10] and biomedical ZnFe 2 O 4 [11]. In the engineering material science field, ferrite nanoparticles are a unique substance from atoms, and molecules, to build ceramics, or devices [12].…”