Background:
Rare earth materials are known for its salient electrical insulation properties
with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel
ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of
Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4
(x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated.
Methods:
A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where
x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural,
morphological and magnetic properties of the samples were examined through X-Ray Diffraction
(XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer
(VSM) measurements.
Results:
XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The
average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited
agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared
to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as
evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+
concentration increases.
Conclusion:
The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform
microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted
samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization
can be explained based on weak super exchange interaction between A and B sites. The difference
in magnetic properties between the samples despite the slight difference in Sm3+ concentrations
suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need,
through the substitution of Fe3+ with rare earth ions.
Polycrystalline to preferred-(100) single crystal texture phase transformation of yttrium iron garnet nanoparticles