Gamma-ray irradiation effects on electrical properties of ferroelectric PbTiO₃ and Pb(Zr_0.52Ti_0.48)O₃ thin films

We investigated gamma-ray irradiation effects on electrical properties of ferroelectric PbTiO₃ (PTO) and Pb(Zr_0.52Ti _0.48)O₃ (PZT) thin films. PTO and PZT thin films were prepared on the Pt/Ti/SiO₂/Si substrates by using a sol-gel method with a spin-coating process. The prepared PTO and PZT thin films were subjected to gamma radiation with various total doses from 0 kGy to 300 kGy. There were no noticeable morphological and structural changes in PTO and PZT films before and after irradiation. As a total dose increases up to 300 kGy, a larger degradation behavior of electrical properties was observed in the PZT films rather than in the PTO films. About 35% of remanent polarization value decreased for the PZT films, while just 10% of that decreased for the PTO films. Dielectric constant of PZT films decreased much from 850 to 580, but that of the PTO films decreased just a little from 400 to 340. This degradation behavior of polarization and dielectric properties can be explained by the pinning of domain walls by some radiation-induced defects. These results suggest that the PTO films have higher radiation hardness properties than the PZT films.