Magnetocrystalline and Surface Anisotropy in CoFe2O4 Nanoparticles.

ABSTRACT: The effect of the annealing temperature Tann on the magnetic properties of cobalt ferrite nanoparticles embedded in an amorphous silica matrix (CoFe2O4/SiO2), synthesized by a sol-gel auto-combustion method, was investigated by magnetization and AC susceptibility measurements. For samples with 15% w/w nanoparticle concentration, the particle size increases from ~2.5 to ~7 nm, increasing Tann from 700 to 900 °C. The effective magnetic anisotropy constant (Keff) increases with decreasing Tann, due to the increase in the surface contribution. For a 5% w/w sample annealed at 900 °C, Keff is much larger (1.7 × 106 J/m3) than that of the 15% w/w sample (7.5 ×105 J/m3) annealed at 700 °C and showing comparable particle size. This indicates that the effect of the annealing temperature on the aniso

SUBMITTER: Omelyanchik A 

PROVIDER: S-EPMC7408426 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature