Nano crystalline Ni 0.5 Zn 0.5 Cr x Fe 2−x O 4 particles with x varying from 0.00 to 0.25 in steps of 0.05 have been synthesized through citrate gel autocombustion method. When Ni 0.5 Zn 0.5 Fe 2 O 4 nano particles were annealed at 1000 o C, the crystallite size increased while the lattice constant decreased slightly. For, the Cr 3+ substituted samples annealed at 1000 o C, the variation in lattice constant, bondlengths, M e -M e distances and other structural parameters have been attributed to the dissimilarity in the ionic radius of the displaced (Fe 3+ ) ion and the substituted (Cr 3+ ) ion. Thermal studies indicated the autocombustion process which is an exothermic reaction between the nitrates salt solutions and the citric acid took place at about a temperature of 400 o C for Ni 0.5 Zn 0.5 Fe 2 O 4 . The M-H loops for all samples indicated a soft ferrite nature for all samples. The non-saturated hysteresis loop and high coercivity for the as prepared Ni 0.5 Zn 0.5 Fe 2 O 4 nano particles has been attributed to the core-shell structure of the fine particles. When annealed at 1000 o C the saturation magnetization of Ni 0.5 Zn 0.5 Fe 2 O 4 nano particles increased and

Ferroelectric and piezoelectric properties of xPb(Mg~/3Nb213)O3-(l-x)Pb (Zro.55Tio.4s)O 3 system have been investigated. X-ray diffraction patterns indicate rhombohedral and cubic structures. Maximum dielectric constant and piezoelectric properties are exhibited by 0"5-0.5 PMN-PZT composition. P is high in 0.6-0"4 PMN-PZT composition.

No abstract

No abstract