Size effect on electrical and magnetic properties of mechanically alloyed CoFe2O4 nanoferrite

Cation distribution of cobalt ferrite electrosynthesized nanoparticles. A methodological comparison

“…Various preparation techniques, such as hydrothermal synthesis [18], coprecipitation [19], sol-gel [20], polymer pyrolysis [21] and mechanical alloying [22] have been reported for producing cobalt ferrites. It has been found that cobalt ferrites of similar composition differ in their magnetic properties depending on the preparation technique, probably owing to different particle size and inversion degree (), which is the fraction of the iron atoms occupying tetrahedral sites.…”

Study of multiferroic properties of Bi2Fe2WO9 ceramic for device application

“…This nature of dielectric relaxation suggests that the hopping mechanism of charge carriers dominates intrinsically at higher temperatures in thermally activated process. 28 The asymmetric broadening of the peaks indicate the spread of relaxation with different time constants, suggesting occurrence of non-Debye type relaxation in the material. 28 Figure 10 depicts the variation of ac conductivity ( ac ) with frequency at some selected temperatures of Bi 2 Fe 2 WO 9 .…”

“…28 The asymmetric broadening of the peaks indicate the spread of relaxation with different time constants, suggesting occurrence of non-Debye type relaxation in the material. 28 Figure 10 depicts the variation of ac conductivity ( ac ) with frequency at some selected temperatures of Bi 2 Fe 2 WO 9 . The value of ac increases with increasing frequency but it is nearly independent at low frequency showing dispersion phenomena obeying the Jonscher's power law equation 33 ; ac ¼ dc þ A!…”

“…27 The impedance analysis of the compound is characterized by the formation of semicircular arcs whose pattern of evolution changes with change in temperature. 28 The extent of intercept of semicircles on the real axis (Z 0 -axis) provides the information on the kind of electrical processes occurring within the material. An equivalent electrical circuit can correlate the semicircles and microstructure of the material.…”

“…Each semicircle is considered as a parallel combination of resistance and capacitance. 28 This semicircular behavior can be explained by the mathematical equation: (Figs. 8(a) and 8(b)) a single semicircle is observed, which confirms only bulk or grain contribution to the impedance data.…”