Influence of thermal annealing on the structural and optical properties of maghemite (γ‐Fe₂O₃) nanoparticle thin films

Abstract

In this study, maghemite (γ-Fe 2 O 3 ) nanoparticles were initially synthesized via chemical co-precipitation and then deposited by spray pyrolysis as thin films on white glass substrates. The thin films were annealed for 8 h at 400, 450, 500, 550, and 600°C in an oven. The structural studies of maghemite nanoparticles were carried out using X-ray diffractometer. Structural properties that we investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, SEM, and Energy dispersive X-ray analysis (EDS). Optical properties of the samples were also investigated by ultraviolet-visible (UV-vis) spectroscopy. The results showed that maghemite nanoparticles have crystalline structure with domain that increases in size with increasing annealing temperature. The optical band gap values were found to reduce from 2.9 to 2.4 eV with increase in annealing temperature.

Tunable polymorphism of epitaxial iron oxides in the four-in-one ferroic-on-GaN system with magnetically ordered α-, γ-, ɛ−Fe2O3 , and Fe3Korovin1, Gastev2, Волков3 et al. 2018Phys. Rev. Materials242230View full textAdd to dashboardCite

“…Below are listed the measured distances between the oxygen planes and the corresponding lattice parameters together with given in parentheses bulk values. The lattice parameters for Fe 3 Interestingly the two extra non-hematite peaks (labeled with question marks in Fig. 10) are present on the α-Fe 2 O 3 specular profile.…”

“…the full L 23 spectral range (a) and the detailed L 3 and L 2 spectra (c, d). Reference data adopted from 11,36,37 is shown for comparison (b).…”

“…Having the largest magnetic moment among the iron oxides (2.66 μ B / formula unit (f.u. ), M s =480 emu/cm 3 , 4πM s = 6000 G) and Néel temperature of 850 K Fe 3 O 4 has been long used in magnetic recording applications. Magnetite is a half-metal with full spin polarization at the Fermi level 1 .…”

“…(M s =380 emu/cm 3 , 4πM s = 4800 G) it is supposed a good candidate to act as a tunnel barrier for the spin filtering devices 2 . Maghemite is also widely used in magnetic storage, gas sensing and biomedical applications [3][4][5] .…”

Facile one-pot chemical approach for synthesis of monodisperse chain-like superparamagnetic maghemite (γ-Fe2O3) nanoparticles

“…Different approaches have been designed for synthesis of maghemite nanoparticles with different morphological structures, including thermal decomposition [2], microemulsion method [3], flame spray pyrolysis [4], plasma chemical synthesis [5], flame synthetic method [6 ], and electrochemical synthesis [7], chemical method [8,9], co-precipitation method [10,11]. Although all these approaches have succeeded to prepare maghemite nanoparticles with good properties, but they used much amounts of surfactant and complicated synthesis procedures, which limit their application potential in the large scale industries.…”