Summary of Findings
Ferrites are the magnetic ceramics of great importance in many technological applications on account of their various electrical, dielectric and magnetic properties. Ferrites with cubic spinel structure form an important class of magnetic materials and exhibit interesting electrical and magnetic properties. Due to their numerous applications ferrites are being studied from last six to seven decades with a view to understand and improve their properties for suitable applications.
During the last decades there has been an interest in developing and understanding the basic magnetic and electrical properties of spinel ferrite at nanometric scale. The progress made in the area of nanotechnology in the recent years has motivated the scientist and technologist to synthesize spinel ferrites in nanometric size and characterize them for their structural, electrical and magnetic properties. It is well known that the properties of spinel ferrites are changed when the size of the particle reduces from bulk to nano.
In the present studies; some novel spinnel ferrite nano materials were synthesized by sol gel auto combustion technique and were characterized by different sophisticated instrumental techniques such as XRD, SEM, magnetization, AC susceptibility etc. and were studied for their magnetic and electrical properties.
The overall report of the project was categorized into four chapters:-
Chapter-I: – First chapter dealing with the materials and methods used.
Chapter-III: – Second chapter describes various properties of ferrites.
- The nanocrystalline Co1+xZrxFe2-2xO4 of different compositions with x = 0.00, 0.05, 0.15 and 0.25) were successfully prepared by sol-gel auto-combustion technique using citric acid as a fuel and AR grade metal nitrates.
- The X-ray diffraction results showed the formation of single phase cubic spinel structure. The crystallite size, lattice constant and X-ray density are in the reported range. The crystallite size confirms the nanocrystalline nature of the samples. The bulk density is quite low compared to X-ray density and hence porosity is increased.
- The grain size determined by linear intercept method from scanning electron microscopy technique is of the order of nanometer range.
- The DC resistivity of all the samples decreases with increase in temperature exhibiting the semiconducting behavior.
- The activation energy in paramagnetic region (Ep) is more than that of ferromagnetic (Ef) region.
The substitution of zirconium ions in cobalt ferrite results in decrease of magnetic properties and increase of electrical properties in general.
- The saturation magnetization (Ms), coercively (Hc) and remanence magnetization (Mr) all these magnetic parameters get decreased as zirconium content x increases in the lattice of cobalt ferrite.
- The magneton number calculated from the values of saturation magnetization also decreases with increase in zirconium content x.
- The substitution of zirconium in cobalt ferrite leads to canting structure.
- The dielectric constant (ε), dielectric loss (ε”) and dielectric loss tangent (tand) decreases exponentially with increase in frequency.
- The peaks observed show compositional dependences as a function of frequency.
- At lower frequencies, it is observed that the dielectric properties are high.
Research Papers published in International Journals:-
- Structural, Microstructural and Magnetic Studies on Zirconium (Zr4+) doped CoFe2O4 Nanoparticles, International Journal of Advanced Research in Basic and Applied Science (IJARBAS), ISSN 2394-4072 (Print)(Accepted).
- Electrical and Dielectrical Properties of Low-Temperature-Synthesized Nanocrystalline Zr4+ doped Cobalt Spinel Ferrite, IJISET – International Journal of Innovative Science, Engineering & Technology, ISSN 2348 – 7968 (Communicated).