Enhanced Electrical and Magnetic Properties of Annealed Magnesium Ferrite Nanoparticles

Abstract

Magnesium ferrite nanoparticles have been prepared by sol–gel auto combustion method, and the effect of annealing on the structural, electrical, and magnetic properties were investigated using thermo gravimetric and differential thermal analysis (TG-DTA), powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), broadband dielectric spectroscopy (BDS) and vibrating sample magnetometry (VSM) techniques. The TG-DTA analysis shows that the prepared sample was thermally stable above 450 ∘C. The PXRD analysis indicates that the crystallite size enhanced from 28 to 42 nm upon annealing. The FTIR spectrum of pristine magnesium ferrite shows a highfrequency vibrational band at 568 cm−1 assigned to tetrahedral site and a lowfrequency vibrational band at 432 cm−1 assigned to octahedral site which are shifted to 572 and 426 cm−1 for annealed samples. FE-SEM analysis shows the agglomerated spherical shaped particles at the surface of pristine magnesium ferrite; the crystallinity and grain size enhanced for annealed sample. The frequency-dependent dielectric constant decreases and tan delta shows a relaxation behavior at low frequencies and AC conductivity decreases for annealed samples compared with pristine. The measured value of saturation magnetization enhances from 15.7 to 33.7 emu/g for 800 ∘C annealed sample and coercivity monotonically decreases from 127 to 95 Oe.