**7. Dielectric constant (εr)**

Variation of dielectric constant and dielectric loss with frequency at room temperature for sintered KNNT thick film is obtained using a metal- insulatormetal structure and the data is shown in **Figure 6**. Dielectric constant value of 320 (at 1 MHz) was obtained for sintered KNNT thick film. The dielectric value of the KNNT film (320) at 1 MHz was lower than the value reported for KNN thick films fabricated via electrophoretic deposition in acetone (393) [21] and aqueous

**Figure 6.**

*Dielectric constant (εr) and tan δ as function of frequency for (left) KNNT thick film sintered at 1000°C (right)MgTiO3 thick films sintered at 800 and 900°C.*

media (495) [20] and the higher values of later two might be the result of dense film obtained by isostatic pressing and higher sintering temperature (1100°C). Dielectric permittivity and loss tangent (tan δ) of MgTiO3 films were evaluated over a frequency range of 1 kHz to 1 MHz, using an impedance analyzer (HP 4284Aprecision LCR Meter). Since the samples sintered at 1000°C were not of good enough quality for electrical studies, the films sintered at 800 and 900°C were used for the studies. Among these two samples, those sintered at 900°C exhibited a good dielectric constant ~18.3 (tan δ ~ 0.0012) at 1 MHz compared to films sintered at 800°C (εr ~ 8.6 and tan δ ~ 0.0031). The low density and porous microstructure can be the reason for low εr values for the films at sintered at 800°C. εr value obtained for samples sintered at 900°C was comparable with that of other literature reports [23, 24].

## **8. Conclusions**

(K0.5Na0.5)(Nb0.7Ta0.3)O3 and MgTiO3 thick films were fabricated successfully by electrophoretic deposition method from TEA added isopropyl alcohol medium and acetone medium, respectively. We suggest that the stability of the KNNT suspension is mainly due to electrostatic stabilization mechanism and the NH<sup>+</sup> (C2H4OH)3 ions being adsorbed on the KNNT particle is responsible for the observed positive surface charge in KNNT particles. From SEM images we confirmed that KNNT particles as well as MgTiO3 particles were well deposited on the substrate and the thickness was found to be ̴32 μm and 18–20 μm (for film sintered at 900°C) respectively. In the case of MgTiO3 thick films, the sintering temperature plays an important role in the quality of films since it affects the density and grain growth. An increase in the sintering temperature, from 800–900°C, resulted in increase in the dielectric constant and reduced loss. Moreover, no cracks were observed on the surface of the thick films, indicating that the processing conditions are favorable to get crack free thick films. The dielectric values of the KNNT and MgTiO3 thick film at 1 MHz was 320 and 18.3 respectively, which is in agreement with the earlier reported values. For these reasons we can say that compared to other solution based techniques EPD is a cost effective and simple technique to fabricate high quality thick films.

### **Acknowledgements**

The authors acknowledge Department of Physics, Central University of Kerala for providing XRD characterization facilities and Maharajas College,

**63**

**Author details**

Vineetha P and Venkata Saravanan K\*

provided the original work is properly cited.

\*Address all correspondence to: venketvs@cutn.ac.in

Tamil Nadu, Thiruvarur, India

Department of Physics, School of Basic and Applied Sciences, Central University of

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*Fabrication of Dielectric Thick Films by Electrophoretic Deposition and Their Characterization*

Ernakulam for SEM facility. VSK. acknowledges the facilities provided by CUTN, UGC for the start-up grant and DST-SERB for the Early Career Research grant (ECR/2015/000273). VP acknowledge the facilities and financial support offered by

*DOI: http://dx.doi.org/10.5772/intechopen.89996*

The authors declare no conflict of interest.

CUTN.

**Conflict of interest**

*Fabrication of Dielectric Thick Films by Electrophoretic Deposition and Their Characterization DOI: http://dx.doi.org/10.5772/intechopen.89996*

Ernakulam for SEM facility. VSK. acknowledges the facilities provided by CUTN, UGC for the start-up grant and DST-SERB for the Early Career Research grant (ECR/2015/000273). VP acknowledge the facilities and financial support offered by CUTN.
