Nanoscale observation of poling behaviors in Nd-substituted Bi 4Ti3O12 ferroelectric thin films

Abstract

In this study, the effects of oxygen vacancies on the local poling properties of Bi-layered ferroelectric thin films were examined. Bi 3.15Nd0.85Ti3O12 (BNT) thin films were coated on Pt(111)/Ti/SiO2/Si substrates using a sol-gel method. An oxygen vacancy of 2.4 ± 0.5% was observed mainly at the Bi 2O2 2+ layers in the film that annealed in an oxygen-deficient atmosphere. The film containing oxygen vacancies showed a shift in the polarization-electric field hysteresis loop. Contact-mode electrostatic force microscopy revealed a domain pinning behavior in the BNT film with oxygen vacancies. The unpolarized domains were explained by the built-in field formed by the oxygen vacancies in the Bi2O2 2+ layers. © 2010 The Japan Society of Applied Physics.