On structural, optical and dielectric properties of zinc aluminate nanoparticles

Abstract

Zinc aluminate nanoparticles with average particle size of 40 nm were synthesized using a sol-gel combustion method. X-ray diffractometry result was analysed by Rietveld refinement method to establish the phase purity of the material. Different stages of phase formation of the material during the synthesis were investigated using differential scanning calorimetry and differential thermogravimetric analysis. Particle size was determined with transmission electron microscopy and the optical bandgap of the nanoparticles was determined by absorption spectroscopy in the ultraviolet-visible range. Dielectric permittivity and a.c. conductivity of the material were measured for frequencies from 100 kHz to 8 MHz in the temperature range of 30-120 • C. The presence of Maxwell-Wagner type interfacial polarization was found to exist in the material and hopping of electron by means of quantum mechanical tunneling is attributed as the reason for the observed a.c. conductivity.

Synthesis and fabrication of GPS patch antennas by using Zn(1 − x)Ti x Al2O4 thin films

“…The E g value for ZnAl 2 O 4 is found to be 3.84 eV (Fig. 5a), which is slightly attributed to other reported by Jamal et al [19]. As TiO 2 increases, the E g was found in the range of 3.40-3.75 eV (Fig.…”

Effects of Pb2+ ions concentration on the structure and PL intensity of Pb-doped ZnAl2O4 nanocrystals synthesized using sol–gel process

“…As anticipated the variation of the mass of the compound with temperature indicates slow weight loss up to 80°C due to the release of interlayer water [4,19]. An event at around 150-200°C, is attributed to the expulsion of hydrated water [4,19,20]. The last event at around 300-400°C is attributed to the elimination of organic compounds and starting of crystallization process and the formation of single phase ZnAl 2 O 4 [4,19].…”

“…The IR spectra of the gel indicate the presence of nitrates groups at 805, 897 and 1,052 cm -1 . The bands at 1,330-1,628 cm -1 can be attributed to the OH group in the metal alkoxides present in the gel [27,28]. The wide absorption band centred at 2,965-3,520 cm -1 corresponds to OH group, which is contributed by the water content present in the gel.…”

“…Figure 3 shows the FTIR spectra of the un-doped ZnAl 2 O 4 gel and annealed at 800°C powder. The band at 682 cm -1 is assign to the stretching vibration of tetrahedral and octahedral bonds in the spinel [4,26,27]. The IR spectra of the gel indicate the presence of nitrates groups at 805, 897 and 1,052 cm -1 .…”

Characterization and effect of calcination temperature on structural properties of spinel zinc aluminate synthesized via Co‐precipitation process

“…1 Introduction Zinc aluminate (ZnAl 2 O 4 ) is typically spinel type of a ternary oxide semiconductor in chemical formula of AB 2 O 4 which zinc cations are in tetrahedra plane (A-sites) and aluminum cations are in octahedral plane (B-sites) surrounded with oxygen anions within facecentered cubic unit cell and Fd3m space group [1]. ZnAl 2 O 4 or natural name in ganite has been recently considered as a functional material in various potential applications.…”