SiO2 modified Co-ferrite with high coercivity

Magnetic and Mossbauer measurements have shown that 1-2 wt% of SiO2 were solved in the CoFe2 O-4 structure after mechanical milling and subsequent heat treatment. Coercivity values up to 3.5 kOe were measured for CoFe2O4/SiO2 powders. High coercivities were also achieved in SiO2 doped Co-ferrite thin films prepared by sputtering technique. The Co-ferrite thin film deposited on silicon wafer using a 5 Wt%-SiO2/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. (C) 2001 Elsevier Science B.V. All rights reserved.