Orientation dependent ferroelectric properties in samarium doped bismuth titanate thin films grown by the pulsed-laser-ablation method

Samarium doped bismuth titanate thin films with the composition of Bi3.25Sm0.75Ti3O12 and with strong preferred orientations along the c axis and the (117) direction were fabricated on Pt/TiO2/SiO2/Si substrate by pulsed laser ablation. Measurements on Pt/BSmT/Pt capacitors showed that the c-axis oriented film had a small remanent polarization (2Pr) of 5 µC/cm2, while the highly (117) oriented film showed a 2Pr value of 54 µC/cm2 at an electrical field of 268 kV/cm and a coercive field Ec of 89 kV/cm. This is different from the sol-gel derived c-axis oriented Bi3.15Sm0.85Ti3O12 film showing a 2Pr value of 49 µC/cm2.