Temperature Dependence of Magnetization, Anisotropy, and Hyperfine Fields of NiFe2–xYbxO4 ( $x = 0$ , 0.05, 0.075)
Temperature dependence of magnetization, anisotropy, and hyperfine interaction parameters of NiFe2-xYbxO4 (x = 0 , 0.05, and 0.075) was investigated, and the results are presented. All the compounds were prepared by solid-state reaction formed in cubic inverse spinel phase with the space group Fd3̅m . Increments in the lattice constant were observed upon partial substitution of Fe3+ by Yb3+. Decreased magnetic moment and increased magnetic anisotropy with Yb3+ substitution were observed through magnetization measurements, carried out at 5, 100, 200 and 300 K. Analyses of Mössbauer spectra recorded at 5 K and 300 K, revealed decreased hyperfine fields and magnetic moments at the B-site (and hence net moment) with increasing Yb3+ content. In addition all the compounds exhibited Neel-type, collinear ferrimagnetic structure.
Combustion synthesis and characterization of Sn4+ substituted nanocrystalline NiFe2O4
Abstract A series of Sn4+ substituted NiFe2O4 with general formula Ni1−xSnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6, and 0.8) has been prepared by novel combustion synthetic method. The prepared compounds have been sintered at 1000 °C and evaluated for their structural and electrical properties. XRD studies reveal the synthesized compounds are nanocrystalline size with cubic structure. The Fourier transform infrared (FT-IR) spectra show the characteristic features of the synthesized ferrite compounds. The UV–vis spectra reveal the optical band gap of the synthesized compounds. The dc electrical conductivity of the compounds found to increase with increasing measuring temperature. A maximum dc electrical conductivity of 6.0 S cm−1 was obtained at a measuring temperature of 1000 °C in the composition of x = 0.8, for which the activation energy for conduction is found to be minimum.
Nickel-zinc ferrites with TiGe substitutions for high-frequency use
Abstract The effect of Fe replacement by Ti and/or Ge on the properties of NiO 0·7 ZnO 0·3 Fe 2 O 4 ferrites manufactured by the classical ceramic method was studied. It was found that the choice of substitution composition may favourably influence the magnetic and electrical properties of ferrites. It is possible to obtain a good soft magnetic material for high-frequency use by optimizing the substitution.