Ferroelectricity in Sodium Nitrite Thin Films

Abstract

Investigations have been conducted on the ferroelectric property of thin films of NaNO2. The thin films were prepared with the dip coating technique. The phase transition was investigated by observing the change in the dielectric constant with temperature change. The presence of ferro-electricity was investigated with a Sawyer-Tower Bridge. UV-VIS absorbance spectroscopy was used to determine the energy band gap and the extinction coefficient at room temperature. It was observed thatNaNO2 thin film undergoes a first order transition from the disordered paraelectric phase to an ordered ferroelectric phase at 162.3�C. Ferroelectricity was confirmed in the NaNO2 thin films by the appearance of a hysteresis loop below the transition temperature. The band gap of the thin film was 3.102 eV. The ferroelectric property exhibited by the NaNO2 thin films do not make it a favourable choice for modern day ferroelectric devices. However, this may be im-proved by doping the thin film with chlorine ions.