Study of complex permeability and secondary effects in some cobalt and manganese based ferrites

Abstract

Polycrystallinc ferrite samples with composition Mn,Fc).,04 with x = 1. 0.75, 0.50 0.25 and CO,FC3.,04 with x = I, 0.75, 0.50 0.25 have been prepared by solid slate reaction. The samples have been studied by X-ray diffraction to check the [anTIalion of the proper fcrrites and their single phase states. The lattice parameters arc also dctcnnined by XRD. The best conditions for the preparation of the samples were found out in respect of sinlcring temperature and calcination time. Ring samples arc prepared for the determination of complex permeability and disk shaped samples are prepared for magnctostriction measurements. The complex permeability measurements are carried out by LCR bridge in the frequency range 1 KHz to 13 MHz. It is observed that CoFe204 sample has initial permeability of 22.03 at I KHz and maximum permeability of 23.8 at 7 MHz. However the permeability of this sample is slightly dependent on frequency and comes down to 21.5 at 13 MHz. The other samples of cobalt based ferrites have relatively low permeability lying between 3 and 5. However permeabilities of these samples are quite frequency independent. Mn ferrites show compositional variation ofpermeabilily. Maximum permeability is obtained for composition MnFe20" the value being abolJt 42 at I KH7. and 40 at 10 KHz frequency. The permeability comes down to 24 at 13 MH;r, frequency. The maximum variation ofpermco.bility with frequency is observed for sample Mnfe104. The other samples with compositions MnO:i5fcl.1S04, Mnu.~nFeljQ04and MnO.2}Fe1.]j04have relatively low permeability, whieh remains almosl steady wilh the whole frequency range. The bcst sampk in respect of permeahility is lhus found to be MnFe20,.