Influence of annealing temperature on microstructural and magnetic properties of Fe₂O₃ nanoparticles synthesized via sol-gel method

Abstract

Using ferric nitrate Fe(NO₃)₃ 9H₂O as a precursor and Ethylene Glycol monoethylene ether as a solvent, Fe₂O₃ NPs were prepared using the sol-gel technique. X-ray diffraction (XRD) study of Fe₂O₃ NPs at different calcination temperatures to determine the size of the crystallite was performed using various methods of calculation showed that crystallite size enhanced to the presence of single phase (γ-Fe₂O₃) at lower temperature, as the contribution of other phase (α-Fe₂O₃) increases in size varies, but again begins to decrease as the material converts to single phase. The average crystallite size of the Fe₂O₃ NPs was 7–11 nm. The synthesized Fe₂O₃ NPs are spherical in shape, according to FE-SEM analysis. The EDX and FTIR spectra of the synthesized particles revealed that they are pure Fe₂O₃ nanoparticles. The magnetic properties of synthesized nanoparticle such as saturation magnetization (Ms) and coercivity (Oe) are calculated from hysteresis curve obtained from Vibrating-sample magnetometer (VSM) data demonstrate that the sample belong to magnetically soft iron oxides and possess a multi-domain structure. The Mössbauer spectral analysis revealed the relative fraction of γ-Fe₂O₃ was more at lower temperature but relative fraction for α-Fe₂O₃ increases as temperature increases which is in quite agreement with structural data.

Keywords:

• Crystallite size
• saturation magnetization
• corecivity
• magnetic field
• Mössbauer spectrometer

Acknowledgements

The authors are grateful to CIR Lab, MNNIT, Prayagraj, for granting permission to use the XRD and VSM facilities. HOD, Department of Chemistry, Lucknow University, Lucknow for allowing the use of FT-IR facility and Director of BSIP, Lucknow for allowing the use of FE-SEM and EDX facility and also thankful to UGC-DAE Consortium for Scientific Research, Indore centre for providing Mössbauer spectroscopy facility.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.