Prof. (Dr). C. H. Bhosale

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Miss. Sarita Kumbhar

under the guidance of

Electrochemical Materials Laboratory,Department of Physics

Shivaji University, Kolhapur 416004December 2013

by

A Presentation on

Synthesis and characterization of spray deposited nickel-zinc ferrite thin films

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Introduction

Methodology

Results and Discussion

1) XRD

2) SEM

3) AC conductivity

4) Dielectric properties

5) Impedance spectroscopy

Conclusions 2

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Outline of the presentation

In recent years, the magnetic materials have more demand in

information and communication technology, because of their high

frequency applications.

Ni-Zn ferrite exhibits favorable properties such as high resistivity,

low eddy current losses and high saturation magnetization.

The trend for down sizing electronic equipment’s and the potential

applications of ferrite materials have lead to the fabrication of ferrites

thin films.

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Introduction

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The bulk component of ferrites can not be compatible with rapid

development of electronic applications.

But, the thin films of ferrite are used in microwave integrated

circuits (MIC), and essential for the miniaturization of magnetic

products.

  Ferrites are the most important magnetic materials, without which

we can not think about technological revolution.

These are very well established group of magnetic materials of the

transition metal oxides.

Ferrites are mixed metal oxides with iron oxide as their main

component having general formula MFe2O4.

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Ferrite

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Classification of ferrites

Soft Ferrite: Ferrites with low coercive force are called soft

ferrites.

eg. Nickel-zinc ferrite, Manganese-zinc ferrite etc.

Hard Ferrite: Ferrites with high coercive force are called hard

ferrite.

eg. Barrium ferrite , Stonsium ferrite etc.

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Spinel Ferrite

The spinel structure is derived from the mineral spinel, which was

first determined by Bragg in 1915.

Spinel ferrites are very stable due to their stable crystal structure,

and they are predominantly ionic.

- A Site ions

- B Site ions

- Oxygen ions

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Octahedral site

Tetrahedral site

664 tetrahedral sites – only 8 surrounded by divalent metal ions (A-Site)

32 octahedral sites – only 16 surrounded trivalent metal ions (B-Site)

Crystal structure of Spinel Ferrite

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Types of spinel ferrite

1) Normal spinel ferrite: [M2+]A[Fe3+2]B O2-

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2) Inverse spinel ferrite: [Fe3+]A [M2+ Fe3+] BO2-4

3) Random spinel ferrite: [M2+x Fe3+

1-x]A [M2+1-xFe3+

1+x]B O2-4

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Methodology

11Schematics of spray pyrolysis showing its various parts

Spray syrolysis set up

Spray pyrolysis is simple and expensive chemical deposition method for producing thin films on large area

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1 Precursors Nickel nitrate, Zinc Nitrate, Ferric nitrate

2 Solvent Water

3 Quantity 30 ml

4 Deposition temperature 400 0C

5 Concentration 0.1 M

6 Spray rate 2 cc/min

Expremental Conditions

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Results and Discussion

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X-ray diffraction patterns for NixZn1-xFe2O4thin films from x = 0.5 to x = 1.0

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Scanning electron micrographs of NixZn1-xFe2O4thin films, from x = 0.5 to x = 1.0 

0.5 0.6

0.7 0.8

0.9 1.0

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Variation of AC conductivity with frequency at room temperature for NixZn1-xFe2O4 thin films

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Variation of dielectric constant with frequency at room temperature for NixZn1-

xFe2O4 thin films

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Complex impedance spectra forNixZn1-xFe2O4thin films from x=0.5 to x=1.0 

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Preparation of NixZn1-xFe2O4 thin films by using spray pyrolysis technique

is possible.

The X-ray diffraction (XRD) analysis reveals that the NixZn1-xFe2O4 thin

films are polycrystalline with spinel cubic structure.

The SEM images show the surface of the film is smooth and having

uniform nature.

The conduction mechanism can be understood from the AC conductivity

studies.

Conclusions

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The dielectric constant decreases with increase in frequency.

The grain boundary behaviour can be studied from the impedance

spectroscopy.

THANK YOU