| Abstract |
BaTiO3(BT)/MnCr0.2Fe1.8O4(MCF) composites were prepared by solid state reaction via sol-gel process
and sintered at 900
C for 1 h. The weight percentages of BT/MCF composites were 0/100, 20/80, 40/60,
60/40, 80/20, 100/0. Phase composition and microstructure of the sintered BT/MCF composites were
characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques,
respectively. Magnetic and dielectric properties of the sintered composites were also studied. The XRD
results showed that all sintered composites exhibit the main phase of tetragonal perovskite structure of
BT and cubic spinel structure of MCF, that the peak intensity of BT phase increases with increasing BT
content. However, BaFe12O19 and a-Fe2O3 extra phases were also observed for all composites. The
microstructure of the composites reveals polyhedral grains for MCF phase and BT phase with the grain
size of about 0.61e1.93mm and 0.51e1.12mm, respectively. All sintered composites present hard ferromagnetic behavior whereas the pure BT and pure MCF are non-ferro/ferrimagnetic and soft magnetic,
respectively. Saturation magnetization (Ms) of the sintered composites tends to decrease with increasing
BT content, giving theMs of 6e19 emu/g andHcof 1.6e2.1 kOe. Dielectric properties of the composites
showed that theεr and tandof all composites derive from ferroelectric BT behavior and hopping conductivity behavior in ferrite phase which is related to Maxwell-Wagner interface polarization model,
leading to dielectric dispersion. The complex impedance spectroscopy indicates the heterogeneous
structure consisting of semiconducting grain and insulating grain boundary.
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Publication
Journal Publication
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