Tailoring the electrical, dielectric and magnetic properties of SiO2 coated NiFe2O4 nanoparticles

Surface modified ferrite nanoparticles with moderate magnetization and stable dielectric properties over the wide frequency range could be of immense importance for various magneto electric applications. The present work is a directed effort, where the investigation of electrical, dielectric and magnetic properties of NiFe₂O₄ and SiO₂ coated NiFe₂O₄ nanoparticles have been carried out. SiO₂ coated NiFe₂O₄ nanoparticles have been synthesized by using sol-gel technique with two different solvents DI water and ethylene glycol and the corresponding samples are nominated as S-NFO1 and S-NFO2. Structurally and morphologically characterized NiFe₂O₄ and SiO₂ coated NiFe₂O₄ are subjected to magnetic and dielectric studies. S-NFO2 exhibits moderate saturation magnetization (∼21 emu/g), stable dielectric properties (dielectric constant ∼ 110 and decreased dielectric loss ∼ 0.2) over wide frequency range and highest non-linear coefficient ∼ 8.4. These modified properties are attributed to the modified microstructure caused by the induced interfacial forces due to the distribution of charged layer at NiFe₂O₄ nanoparticle and SiO₂ interface. The present study could be a strategic pathway for synthesizing the surface modified ferrite nanoparticle for the new age magneto electric applications.