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