Double-hysteresis-like loops in Cr2Ti3O9-doped BaTiO3 ceramics

• Double-hysteresis-like loops were found in BaTiO3-based ceramics.
• The displacement of oxygen octahedral drive this phenomenon.
• It can transform into a normal one with temperature rising.

Barium titanate (BaTiO3) ceramics doped with different content of Cr2Ti3O9 were obtained by sintering in a temperature rang from 1300 to 1350 °C in air for 2 h. The phase composition, perovskite structural parameters and ferroelectric properties have been obtained by X-ray diffraction and ferroelectric measurements as a function of chemical composition and temperature. At low doping levels the peculiar double-hysteresis-like loops were found to have striking similarities to aging tetragonal ferroelectrics, besides following random local strains mechanism driven by the displacement of oxygen octahedral in shrunk crystals caused by phase transition. The polar moments surrounding the shrunk crystal cells were partially aligned and disrupted the long-range polar order due to the different final polarization direction by coupling between spontaneous polarization in original lattice. With temperature rising, the double-hysteresis-like loops can transform into a normal one because of the increase of long-range polar order.