Ferroelectricity enhancement in ferroelectric nanotubes

Abstract

In this article we study the size effects of the ferroelectric nanotube phase diagrams and polar properties allowing for effective surface tension and depolarization field influence. An approximate analytical expression was derived for the dependence of the paraelectric-ferroelectric transition temperature on the radii of nanotube, polarization gradient coefficient, extrapolation length, surface tension and electrostriction coefficient. It was shown that the transition temperature could be higher than the one of the bulk material for the negative electrostriction coefficient. Therefore, we predict conservation and enhancement of polarization in long ferroelectric nanotubes. The obtained results explain the observed conservation and enhancement of ferroelectricity in Pb(Zr,Ti)O₃ and BaTiO₃ nanotubes.

Keywords:

• Ferroelectrics
• Size effects
• Nanotubes