Influence of additives on the magnetic and electrical properties of iron-excess Mn-Zn ferrites

Abstract

Iron-excess Mn-Zn ferrite samples with and without additives are prepared by ceramic method and are subjected to different sintering c011ditions The additives, used in this work are V205, Ti02 and CoO in the composition rvln",IZnr44Fclo504 and CuO substitutes m the sample Mn",_ ,('u,Zn~21Fe2 US04'For characterization and delennination of lattice parameters, X-lay diffraction JS canied oul. Cmie temperature measurements, l11aglletizalion measurements, pelmeability measurements and microstructure study arc performed for the understanding of the magnetic properties of the prepared samples as modified by compositional change, additives and heat treatment. X-ray diffraction results indicate that samples are in good clystalline fonn, 1'10111Curie temperahlre measurements, a decreasing trend in the Curic temperature is observed for the substitution of Cu2' for Mn". The Curie temperature is found to be velY sensitive for the additives like VzOj, TiO] and CoO. The magnetization measurements reveal that crystal site preference can stgnificantly affect the saturation magnetization, M" The saturation magnetization increases for 1'= 0.03 in Ivftl<],7_,Cu~Zl1{o22Fe2oaiOnd-l then decreases for fmther increase of Cu]+ content. Saturation magnetization significantly increases by the addition of CoO in MnOjIZnU4-lFe211501. But it decreases for thc addition of TiO] and V20j and the effect is drastic for V20j doped sample than for TiO] ones. The microstJUcture study show that grain size increases with sintering tcmperature, TIle quenchcd ,amp1es have smallcr grain size and almost unifollll in size. From petmeability spectra, it is noticed that sinteJing condition and additives substantial1y affect the permeability valnes. Quenched samples are found to possess higher permeability. From 10 KHz to 1 MHz, for all thc samples the penneability is found to remain almost frequency independent. The loss factors and quality factors are also calculated and this study revealed that sintenng condition is a detennining factor for high quality Mll-Zn femtes. It has been found that the sample Mnu7.xCu,Zno22Fe]n~04 with 1'=0.15 has the best composition for high permeability