Molecular-dynamics investigation on polarization retention of barium titanate nanofilm arising from ordered oxygen vacancy

¹ Department of Mechanical Engineering, The University of Hong Kong - Hong Kong, PRC
² School of Physics and Nuclear Energy Engineering, Beihang University - Beijing 100191, PRC
³ State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences - Beijing 100190, PRC

^a aksoh@hku.hk

Received: 25 May 2010
Accepted: 22 September 2010

Abstract

Molecular-dynamics simulations have been carried out to investigate the electric hysteresis of barium titanate nanofilm containing oxygen vacancy ordering array parallel to the {101} crystal plane. The results obtained show a significant weakening of polarization retention from non-zero value to zero as the size of the array was reduced to a critical level, which was attributed to the formation and motion of head-to-head domain wall structure under external field loading process. By comparing with materials containing isolated oxygen vacancies, it was found that the zero retention was due to the oxygen vacancy ordering array rather than to the concentration of oxygen vacancy.