Mechanical Milling Induced Improvement In Magnetic Property Of Nanosized Ni[sub 0.35]Zn[sub 0.65]Fe[sub 2]O[sub 4]: A Hyperfine Characterization

Abstract

The magnetic properties of nano‐sized Ni0.35Zn0.65Fe2O4 prepared by high‐energy ball milling have been investigated using dc magnetization. The study on relaxation dynamics of the system using Mössbauer spectroscopy is also reported. The Mössbauer spectrum at 300 K exhibits hyperfine split sextet and a superparamagnetic behaviour has been observed at 500 K. The sample has shown enhancement in magnetization, magnetic hyperfine field and anisotropy energy, which appears to be unusual according to core‐shell model. The results indicate that at 300 K the spontaneous reversal of magnetization vector owing to superparamagnetic relaxation of nanoparticles has reduced significantly due to the increase in anisotropy energy. These properties could be profitably used to conquer the inherent instability of magnetic nanoparticles.