Impact of B-site Hf~(4+)-doping on the structural and ferroelectric properties of Bi_4Ti_3O_(12) thin films

摘要

Hf~(4+)-doped and undoped (028)-oriented Bi_4Ti_3O_(12) ferroelectric films with the same thickness have been deposited on two SrRuO_3-covered (111)-oriented SrRuO_3 substrates by pulsed laser deposition (PLD). The structures of the twofilms were studied by x-ray diffraction (XRD). It was found that the Hf~(4+) ion doped at site B has greatly improved the remnant polarization and fatigue property. That because the Hf ion has changed the structure of Hf~(4+) -doped Bi_4Ti_3O_(12) film a lot including a tensile strain along a axis, a triple-domain structure and distortion of oxygen octahedral which result in an increase of the remnant polarization. And the triple-domain structure and the reduction of oxygen vacancies also caused by Hf~(4+) ion doping improved the fatigue property.