The Study of Annealing and Coating Method of CoFe₂O₄ Thin Films Fabricated by Sol-Gel Method

Abstract

CoFe₂O₄ (CFO) thin films were prepared on the Si (100) substrates by a sol-gel method. Their microstructure and magnetic properties were analyzed and measured by XRD, AFM and VSM. The experiment results show that the films have a single phase of the spinel structure when the annealing temperature is above 450°C. The crystallization degree and the Ms of the CFO thin films increase slowly with the increase of the annealing temperature. The grain size achieves the single-domain critical size at about 650°C, which cause Hc starts to drop with the rise of annealing temperature. The CFO thin films prepared by crystalline multi-layered coating method have bigger grain size, worse compactness and bigger Ms than those prepared by non-crystalline multi-layered coating method.

Keywords:

• Sol-gel method
• thin films
• surface topography
• coercivity
• saturation magnetization