Effect of annealing temperature on the magnetic properties of CoFe₂O₄ nanoparticles

Abstract

Nanocrystalline CoFe₂O₄ samples were prepared using the flash technique and annealed at different temperatures. X-ray diffraction results indicate a single-phase spinel structure. The saturation and remanent magnetization of the samples have been determined as a function of the crystallite size. An exponential decay of the coercive field with crystallite size is observed. After annealing, one of the samples at 950°C, 40 nm particles were obtained with a saturation magnetization of 64.36 emu/g, a coercivity of 396 Oe and the highest density among all the samples.

Keywords:

• nanostructures
• magnetically ordered materials
• CoFe₂O₄
• flash method
• saturation magnetization
• coercivity

Acknowledgement

The author is grateful to Professor Dr M.A. Ahmed, Materials Science Laboratory (1), Physics Department, Faculty of Science, Cairo University, Giza, Egypt, for his invaluable help during the progress of this work.