Unusual size effect on the polarization patterns in micron-size Pb(Zr,Ti)O3 film capacitors

Abstract

Direct observation of polarization distribution at nanoscale by scanning force microscopy across partially etched Pb(Zr,Ti)O3 film ferroelectric capacitors with size 2×3 μm and preferential orientation (111) has revealed an anomalous polarization pattern characterized by polarization inversion in the center of the capacitor. This self-structured pattern is reproducible and independent on the spontaneous polarization orientation, but strongly influenced by the film texture and capacitor size. In particular, capacitors of the same texture with size 0.5×0.5 μm as well as capacitors with (100) preferential orientation of any size did not exhibit such anomalous polarization distribution. A tentative explanation consistent with the essential features of the observed polarization behavior in terms of strain-induced phase transition is discussed.