Effect of manganese substitution on magnetoimpedance and magnetostriction of cobalt ferrites

Influence of manganese substitution on the magnetoimpedance ratio and magnetostrictive constant of cobalt ferrite samples has been studied in the present investigation. Magnetoimpedance was found to vary with manganese content and frequency under the action of applied axial magnetic field. Maximum value of magnetoimpedance ratio was obtained for the composition Co1.1Mn0.1Fe1.8O4 at a low frequency of 102 Hz. In order to understand magnetoimpedance behavior of the samples Cole-Cole plot of Mn substituted cobalt ferrites was studied. It was also noted that magnetostrictive constant under applied dc magnetic field changes with manganese content. The magnetic field required for maximum magnetostriction decreases with substitution of cobalt by manganese in Co1.2−xMnxFe1.8O4. The strain sensitivity ratio dλ/dH was maximum for Co1.1Mn0.1Fe1.8O4, whereas value of magnetostriction was maximum for CoMn0.2Fe1.8O4 sample.