Periodic arrays of flux-closure domains in ferroelectric thin films with oxide electrodes

摘要

Flux-closure domain structures in ferroelectric thin films are considered to have potential applications in electronic devices. It is usually believed that these structures are stabilized by the depolarization field and the contact with electrodes tends to screen the depolarization field and may limit their formation. In this work, the influence of oxide electrodes (SrRuO_3 and La_(0.7)Sr_(0.3)MnO_3) on the formation of flux-closure domains in PbTiO_3 thin films deposited on (110)-oriented GdScO_3 substrates by pulsed laser deposition was investigated by Cs-corrected transmission electron microscopy. It is found that periodic flux-closure domain arrays can be stabilized in PbTiO_3 films when the top and bottom electrodes are symmetric, while a/c domains appear when asymmetric electrodes are applied. The influence of asymmetric electrodes on the domain configuration is proposed to have a connection with their different work functions and conductivity types. These results are expected to shed light on understanding the nature of flux-closure domains in ferroelectrics and open some research possibilities, such as the evolution of these structures under external electric fields.