EFFECT OF Ni ON THE ELECTRICAL AND MICROSTRUCTURAL PROPERTIES OF NANOCRYSTALLITES Fe2O3/TiO2 SYSTEM
MAGED S. SOBHY
Nominal compositions of NixTi1-xFe2O5-Î´ (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by a solid state reaction using stoichiometric amounts of Fe2O3/TiO2 system and NiO as a dopant. The effects of small substitution of Ni ions on the electrical and structural properties were studied for the above system. The X-ray diffraction patterns revealed that the ferroelectric phase of iron titanate and the spinel ferrite phase of Ni-ferrite having a single phase at x = 0 and 1, respectively. The substitution of Ni ions increases the average value of lattice constant aav. Solidâsolid interaction took place between the ternary oxides at 1200Â°C for 4 h yielding a new phase of NiTiO3. The presence of the three phases was confirmed by X-ray diffraction technique. The resultant compositions have nanocrystallites with average crystalline size "Dav" in the range 100â300 nm. The DC electrical resistivity Ï, Curie temperature TC and activation energies for electric conduction around TC region increase as Ni ion substitution increases. The ferrite samples have a semiconductor behavior where electrical resistivity Ï decreases on increasing temperature. The activation energy for electrical conduction was affected by both the ratio "ferroelectric/ferrite" and the position of the Curie temperatures in the compositions depending on the (Ni, Ti) to Fe ratio.
Magnetic semiconductor ferrites, ferroelectric/ferrite nanocrystallites system, X-ray diffraction, resistivity, Curie temperature
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