Influence of vacuum sintering on microstructure and magnetic properties of magnetostrictive cobalt ferrite

• Published in: Journal of magnetism and magnetic materials 2009-09, Vol.321 (17), p.2528-2532
• Main Authors: Nlebedim, I.C., Ranvah, N, Williams, P.I., Melikhov, Y, Anayi, F, Snyder, J.E., Moses, A.J., Jiles, D.C.
• Format: Article
• Language: English
• Subjects: Anisotropy coefficient; Cobalt ferrite; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetoelastic property; Magnetomechanical and magnetoelectric effects, magnetostriction; Magnetostriction; Physics; Vacuum sintering
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2009.03.021

Differences in the microstructure and magnetic properties of highly magnetostrictive cobalt ferrite resulting from the effects of different vacuum sintering temperatures and times have been investigated. A vacuum environment was chosen to allow direct comparison of results with air-sintered samples which are more often reported in the literature. It was found that vacuum sintering resulted in the development of a solid solution second phase with composition Co 1− x Fe x O 4 ( x∼0.33). There was a decrease in magnetostriction as a result of the formation of the second phase. Furthermore, differences in sintering temperatures were found to have a greater effect on the magnetostriction than differences in sintering times. It was found that the first order cubic anisotropy coefficient initially increased with both sintering temperature and time, before peaking and decreasing to its lowest measured value. The lowest anisotropy was therefore achieved with samples sintered at higher temperatures and longer times.