EFFECT OF Ni ON THE ELECTRICAL AND MICROSTRUCTURAL PROPERTIES OF NANOCRYSTALLITES Fe₂O₃/TiO₂ SYSTEM

Abstract

Nominal compositions of NixTi 1−x Fe 2 O 5−δ (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by a solid state reaction using stoichiometric amounts of Fe 2 O 3 /TiO 2 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. Solid-solid interaction took place between the ternary oxides at 1200 • C for 4 h yielding a new phase of NiTiO 3 . 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 100-300 nm. The DC electrical resistivity ρ, Curie temperature T C and activation energies for electric conduction around T C region increase as Ni ion substitution increases. The ferrite samples have a semiconductor behavior where electrical resistivity ρ 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.

Polarization Properties of Ferroelectric Thin Films Under Different Boundary Conditions

“…Over the past years, a significant amount of research has been devoted to investigate the ferroelectric materials under different BC both experimentally [6][7][8][9][10][11][12] and theoretically. [13][14][15][16][17][18][19][20][21][22] However, up to now, no adequate transverse field Ising-type model was developed in theoretical BC investigations, which has been widely applied to study the properties of ferroelectric thin films with surface layers.…”