Flexoelectric response in BaTiO3-based ceramics doped by transition group elements V, Mn and Ni

It is well known that doping can significantly affect the dielectric and eletromechanical properties of perovskite ferroelectrics like BaTiO 3 . However, the influence of transition group element doping on the flexoelectric property of BaTiO 3 -based ceramics remains poorly studied. Here, we made a comparative investigation on the flexoelectric property of BaTiO 3 -based ceramics doped by transition group elements V, Mn and Ni. The phase composition, crystal structure, and average grain size of the ceramics were determined using X-ray diffraction refinement and scanning electron microscopy. It shows that the samples all exhibit dense and uniform microstructures with clear grain boundaries, but they have different average grain sizes ranging from 15 to 59 μm. Ceramics with larger average grain sizes exhibit higher dielectric constants and Curie temperatures. While the flexoelectric coefficient of Ni-doped, V-doped and pure BaTiO 3 ceramics varies from 15.36 μC/m to 60.37 μC/m, showing positive correlation with average grain sizes, that of the Mn doped BaTiO 3 ceramic which has the largest average grain size (59 μm) is rather small (19.01 μC/m). We suggest that the increased conductivity of ceramics suppresses the flexoelectric effect. The factors determining the flexoelectric coefficient of BaTiO 3 based ceramics doped by transition group elements should include electrical conductivity in addition to dielectric constant which is further affected by grain size. Our work gains new insight into the flexoelectric effect in perovskite oxide ceramics.