Structural, optical and magnetic properties of Ni1−xZnxO/Ni nanocomposite

Abstract

Ni 1−x Zn x O/Ni nanocomposite samples synthesized by wet chemical method were characterized by X-ray powder diffraction, Fourier Transform Infrared (FTIR) spectrometer, UV-Vis spectrometer and Nine Tesla Physical Property Measurement System (PPMS)-based vibrating sample magnetometer (VSM). XRD spectra contained peaks due to NiO and Ni. Rietveld refinement of XRD data indicated the change in lattice parameter is more than twice in NiO than in Ni suggests that Zn goes more favorably into NiO than in Ni. The band gap of NiO in Ni 1−x Zn x O/Ni samples increased from 3.58 to 3.81 eV with increasing x from 0 to 0.07 and thereafter the band gap slightly decreases. NiO/Ni nanocomposites show strong room temperature ferromagnetism. The ferromagnetic interaction further enhanced with 1% of Zn doping into NiO in NiO/Ni nanocomposite. Beyond this doping concentration, the magnetic interaction does not show any systematic variation. The observation of room temperature ferromagnetism in nanocomposite samples is explained by combining the effect of bound magnetic polaron and the magnetization of system with the distribution of magnetic ions as meagerly dispersed in large clusters. Our study indicated that Ni 0.99 Zn 0.01 O/Ni nanocomposite sample could be useful for magnetic recording device application.

Effect of annealing duration on the structural, optical and magnetic properties of NiO/NiFe2O4 nanocomposites

“…Here, hν represents the photon energy, and B is a constant parameter specific to the material. The linear behavior observed in the plot of (αhν) 2 versus hν (figure 5) suggests that the synthesized NCs obey the characteristics of direct E g semiconductors [32]. The specific direct E g values (table 3) for the NCs are determined by extending the linear portion of the (αhν) 2 versus hν plot to α = 0.…”

“…UV-Visible analysis was conducted to explore the influence of different annealing durations on the E g of the prepared NCs. The value of direct E g of the NCs were determined using Tauc's plot [32,45] methodology from…”

“…Also, by virtue of the EB effect, such bi-phasic NCs are reported to possess potentiality to elevate the hard magnetic features of permanent magnets [30], surmount the superparamagnetic edge in magnetic recording media [25] and become useful in applications like magnetic random-access memory, switching devices, etc [31]. NiO being an AFM material having high Neel temperature (T N = 523 K) [32] and NiFe 2 O 4 being the FIM materials with elevated Curie temperature (T c = 858 K), become the synergistic combination to realize EB effect [33].…”

Chemical fabrication, structural characterization and photocatalytic water splitting application of Sr-doped SnO2 nanoparticles

“…Furthermore, on the transmission spectra, Kubelka-Munk equation was employed to calculate the band gap as: F(R)=α/s=(1 − R) 2 /2R; the terms in the above equation like F(R), α, s and R denote the Kubelka-Munk function, absorption coefficient, scattering factor, and reflectance of the as-synthesized SnO 2 and Sr-doped SnO 2 nanostructures, respectively. An intercept of the Taucs plot between αhυ 2 on y-axis and hυ on x-axis as shown in figure 9 provides the values of the band gap of as-synthesized materials [43][44][45]. The band gap values were found to be 3.56 eV, 3.54 eV, 3.12 eV and 3.03 eV for pure SnO 2 , 1%, 2.5% and 5% Srdoped SnO 2 nanoparticles, respectively.…”

Fabrication of tunable band gap carbon based zinc nanocomposites for enhanced capacitive behaviour

“…Further increase in concentration of Zn NO H O . Tauc and Davis-Mott relation [42] as given in equation (6) below is used to calculate the bandgap of as obtained samples which are shown in table 3.…”