Effect of cerium concentration on the structural and ferroelectric properties of Bi4−xCexTi3O12 thin films for ferroelectric random access memories

The effect of cerium concentration on the structural and ferroelectric properties in Bi4−xCexTi3O12 (BCT) thin films grown using pulsed-laser deposition was studied. The BCT films with x=0.25 and 0.5 have a pure layered structure after annealing at 650°C in an oxygen ambient. On the other hand, films with x=0.75 still contained a pyrochlore phase as well as a layered structure. The remanent polarization of BCT thin films decreased with increasing Ce concentration. The BCT films with x=0.25 and 0.5 exhibit no polarization fatigue after electric field cycling up to 6×1010 switching cycles. The leakage current densities of samples measured at 100kV∕cm decreased slightly with decreasing Ce concentration.