Observation of domain structures in Bi-based CaBi4Ti4O15 thin films by scanning force microscopy

Piezoresponse scanning force microscopy (Piezo-SFM) is applied to investigate the domain structures in polycrystalline CaBi4Ti4O15 (CBT) ferroelectric thin films prepared by a chemical solution deposition on Si substrate. By monitoring the vertical and lateral deflection signals from the SFM cantilever, we can visualize the out-of-plane and in-plane polarization vectors in the films individually. We show that the grains in the films consist of wedge-like multi-domains with polarization vector sloped away the thickness direction. A spatial distribution of piezoresponse has been observed in the films.