“…10 b. Also when the grain size is enhanced at a high annealing temperature (800 °C), as mentioned in TEM results, the grain boundaries are reduced, therefore, this decreases the scattering of carriers at grain boundaries, so that the E g value can be diminished 51 . In Zn-doped NiFe 2 O 4 despite the decrement in crystallite size of ZNFO from XRD data because of increment in the degree of the structural disorder means greater dislocation density, lattice strain, and micro-strain according to XRD results in Tables 4 and 5 , the sub-bands formed and merged between the band gap which formed a continuous band that reduced the band gap energy of ZNFO spinel ferrite 52 as shown in Fig.…”
Section: Resultsmentioning
confidence: 84%
“…Also, synthesized methods and conditions can be important in this characterization 56 . This condition often implies excellent electronic properties, such as high carrier mobility and low density of localized states 51 , 57 . Figure 12 Plots of Urbach energy against photon energy (hν) for ( a ) NFO, ( b ) MNFO, ( c ) ZNFO.…”
MxNi1-xFe2O4 spinel ferrite (M = Mn, Zn, and x = 0, 0.05) has been successfully synthesized by co-precipitation technique with hydrazine hydrate reduction agent (instead of NaOH) and Ethylene glycol surfactant. The XRD spectra of the samples illustrated high crystallinity. The structural characterization of pure and doped fcc NiFe2O4 were calculated by Scherrer, Modified Scherrer, Williamson–Hall, and SSP methods. In comparison of several methods, the Scherrer method is unreasonable method and W–H method has an acceptable range and can calculate both < L > and strain without restriction. The specific surface area in Zn-doped increased, demonstrate increment of adsorption properties in Ni ferrite structure. TEM images revealed the shape of grains is spherical, cubic, and irregular, with a grain size in the range of 35–65 nm. Hysteresis loops illustrated the magnetic behavior of samples. From the reflectance data, the band gap energies were estimated at 1.984, 1.954, and 1.973 eV for un-doped, Mn, and Zn-doped NiFe2O4 respectively (red shift). The almost low value of Urbach energy for pure, Mn, and Zn -doped NiFe2O4 indicates low structural disorder, which can approve the high crystallinity of samples. Direct band gap energy (Eg), refractive index, and extinction coefficient were estimated by the Kramers–Kronig method with linear optical evaluations. The Eg by K-K method is in good agreement with the Eg by Kubelka–Munk function.
“…10 b. Also when the grain size is enhanced at a high annealing temperature (800 °C), as mentioned in TEM results, the grain boundaries are reduced, therefore, this decreases the scattering of carriers at grain boundaries, so that the E g value can be diminished 51 . In Zn-doped NiFe 2 O 4 despite the decrement in crystallite size of ZNFO from XRD data because of increment in the degree of the structural disorder means greater dislocation density, lattice strain, and micro-strain according to XRD results in Tables 4 and 5 , the sub-bands formed and merged between the band gap which formed a continuous band that reduced the band gap energy of ZNFO spinel ferrite 52 as shown in Fig.…”
Section: Resultsmentioning
confidence: 84%
“…Also, synthesized methods and conditions can be important in this characterization 56 . This condition often implies excellent electronic properties, such as high carrier mobility and low density of localized states 51 , 57 . Figure 12 Plots of Urbach energy against photon energy (hν) for ( a ) NFO, ( b ) MNFO, ( c ) ZNFO.…”
MxNi1-xFe2O4 spinel ferrite (M = Mn, Zn, and x = 0, 0.05) has been successfully synthesized by co-precipitation technique with hydrazine hydrate reduction agent (instead of NaOH) and Ethylene glycol surfactant. The XRD spectra of the samples illustrated high crystallinity. The structural characterization of pure and doped fcc NiFe2O4 were calculated by Scherrer, Modified Scherrer, Williamson–Hall, and SSP methods. In comparison of several methods, the Scherrer method is unreasonable method and W–H method has an acceptable range and can calculate both < L > and strain without restriction. The specific surface area in Zn-doped increased, demonstrate increment of adsorption properties in Ni ferrite structure. TEM images revealed the shape of grains is spherical, cubic, and irregular, with a grain size in the range of 35–65 nm. Hysteresis loops illustrated the magnetic behavior of samples. From the reflectance data, the band gap energies were estimated at 1.984, 1.954, and 1.973 eV for un-doped, Mn, and Zn-doped NiFe2O4 respectively (red shift). The almost low value of Urbach energy for pure, Mn, and Zn -doped NiFe2O4 indicates low structural disorder, which can approve the high crystallinity of samples. Direct band gap energy (Eg), refractive index, and extinction coefficient were estimated by the Kramers–Kronig method with linear optical evaluations. The Eg by K-K method is in good agreement with the Eg by Kubelka–Munk function.
“…In addition to their magnetic and electrical properties, spinel ferrites also exhibit interesting optical properties. These properties have been investigated in recent years for their potential applications in fields such as optoelectronics, photonics, and optical sensing [7,8]. This chapter primarily focuses on spinel ferrite as an illustrative example.…”
Spinel oxides have a pivotal role in material science due to their structural, electrical, magnetic and optical properties, rendering them essential for wide range of applications. Spinel oxides, characterized by their spinel crystal structure, belong to a group of inorganic compounds with a general chemical formula of AB2O4, where A and B represent distinct metal ions. These compounds are frequently encountered in minerals, rocks, and soils, and their versatility makes them invaluable in numerous domains, including catalysis, energy storage, electronics, and ceramics. This paper briefly reports existing fascinating structural, opto-electronic properties of some spinel oxides, to understand electronic band structure, density of states and optical properties such as dielectric function, refractive index, absorption, reflectivity and optical conductivity for their applications in engineering devices. Basically, spinel compounds have physical properties such as high reflectivity, high melting point, high strength and chemical resistivity at elevated temperatures as well as low electrical loss. Therefore, we have made an attempt to showcase considered properties of these materials at one place.
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