Polarization Relaxation Induced by Depolarization Field in Ultrathin Ferroelectric BaTiO$_3$ Capacitors

TL;DR

This study investigates how depolarization fields cause polarization relaxation in ultrathin BaTiO3 ferroelectric capacitors, revealing that internal fields significantly impact device stability and size limitations.

Contribution

It provides experimental and theoretical analysis of depolarization fields causing polarization relaxation in ultrathin ferroelectric capacitors, highlighting a critical size limit.

Findings

Depolarization field values match electrostatic calculations.

Large depolarization fields induce severe polarization relaxation.

Size limits for ferroelectric devices are affected by this relaxation.

Abstract

Time-dependent polarization relaxation behaviors induced by a depolarization field $E_{d}$ were investigated on high-quality ultrathin SrRuO$_{3}$/BaTiO$_{3}$/SrRuO$_{3}$ capacitors. The $E_d$ values were determined experimentally from an applied external field to stop the net polarization relaxation. These values agree with those from the electrostatic calculations, demonstrating that a large $E_{d}$ inside the ultrathin ferroelectric layer could cause severe polarization relaxation. For numerous ferroelectric devices of capacitor configuration, this effect will set a stricter size limit than the critical thickness issue.