Switching related activation field for polarization-reversal and for polarization-saturation in NaNO₂-PVA thin composite films

Abstract

The remanant polarization in ferroelectric materials appear due to some lattice hindrances which do not allow the domains and their constituting unit cells to relax back to their previous orientations at zero value of sweeping field. This tendency appears in the form of capacitance due to shaking-up of the positive and negative charge centers of the structural unit cells in every domain leading to movement of charges throughout the system. It is this kind of movement and not the permanent dipole moment of the charges in the ferroelectric sample which becomes the cause of capacitance and hence helps the system to store energy from the applied electric field over there; the stored energy in the ferroelectric sample can be stripped off with the application of some minimum reverse field called activation field for polarization reversal. Landauer modeled average polarization current over the switching time and related rate of polarization switching with some minimum applied field below which polarization switching shall be too slow to attain saturation stage of polarization during the life time of the experiment designed for the purpose and accordingly the sample, in spite of being ferroelectric, shall not translate to ferroelectric hysteresis loop. In this paper ferroelectric switching analysis of equal wt% NaNO₂-PVA composite fabricated at elevated temperature is carried.

Keywords:

• Backswitching
• lattice hindrances
• Landau theory
• polarization reversal
• polarization saturation

Acknowledgements

The authors acknowledge IKG Punjab Technical University Jalandhar-Kapurthala highway Kapurthala, Punjab (India) and Maharaja Ranjit Singh Punjab Technical University Bathinda, Punjab (India) for providing research facilities. The cooperation and help rendered by the staff of Department of Applied Physics, Giani Zail Singh Campus College of Engineering and Technology Bathinda is also acknowledged. In addition, the first three authors acknowledge their parent institution Punjabi University Patiala, Punjab (India) for granting permission to pursue research work.