Evaluation of Structural, Micro-structural, Vibrational and Elastic Properties of Ni–Cu–Zn Nanoferrites: Role of Dopant Cu2+ at Constant 0.1 mol% in Ni–Zn Spinel Structure

Abstract

Structural and elastic properties have been investigated for a series of heat treated NixCu0.1Zn0.9−xFe2O4 (x = 0.5, 0.6, 0.7) nanoferrite powders which were synthesized using co-precipitation method. Rietveld refinement patterns revealed the spinel phase belonging to fd3m space group. Lattice parameters of the heat treated samples are in the range of (8.453–8.417 A). As the substitution level of Ni2+ increased, the lattice parameter decreased in the samples sintered at 200 °C, but it was randomly varied in the in the samples sintered at 500 °C. The average crystallite size (4.1–10.9 nm) estimated from XRD as well as average particle size (5.5–11.3 nm) estimated from FE-SEM were found to be increased with the increase of Ni2+ ion concentration in sintered ferrite samples. Sintering process was promoting the growth of nanoparticle size. The spherical nature of ferrite nanoparticles was evident from the FE-SEM micrographs. The vibrational bands observed in the FTIR spectra confirm the cubic spinel phase of ferrite systems. The variation of vibrational bands seems to be dependent on the particular metal ion occupying the spinel structure rather than the changes in bond lengths of Fe3+–O2− ion complexes. The present values of elastic moduli revealed the mechanical hardness of present heat treated ferrite samples. Interestingly, the elastic moduli depend upon the variation of both inter-atomic distances as well as cation redistribution. The identical value of Poisson’s ratio (0.35) is an authentication of isotropic behaviour of the present ferrite systems.