SiO 2 modified Co-ferrite with high coercivity

Abstract

Magnetic and Mössbauer measurements have shown that 1–2 wt% of SiO 2 were solved in the CoFe 2O 4 structure after mechanical milling and subsequent heat treatment. Coercivity values up to 3.5 kOe were measured for CoFe 2O 4/SiO 2 powders. High coercivities were also achieved in SiO 2 doped Co-ferrite thin films prepared by sputtering technique. The Co-ferrite thin film deposited on silicon wafer using a 5 wt%–SiO 2/Co-ferrite target possessed a coercivity of 7.4 kOe, which is the highest value in Co-ferrite and spinel materials according to our knowledge.