Thickness-dependent magnetic anisotropy in laminated Co_1.1Fe_1.9O₄ ceramics

The Co_1.1Fe_1.9O₄ ferrite with high magnetic anisotropy has great potential to be applied in sensors, transformers, and magnetic recording, etc. However, there are few researches about improving the magnetic anisotropy of Co_1.1Fe_1.9O₄ ferrite. In this work, the tape-casting method was adopted to fabricate laminated Co_1.1Fe_1.9O₄ ceramics. Their relative densities are all higher than 95%, and their magnetic anisotropies especially for ΔM_r (the percentage residual magnetization between in-plane and out-of-plane) and ΔH_C are considerably enhanced by this method comparing with that of the Co_1.1Fe_1.9O₄ ceramic prepared by traditional solid-state reaction. It is also found that the magnetic anisotropies of these laminated Co_1.1Fe_1.9O₄ ceramics are thickness-dependent probably due to the effect of grain size, that is, the magnetic anisotropies can be stronger when reducing the thickness of the sample. This provides a new approach to improve the magnetic anisotropy of ferrites for electronic devices applications.