Structural properties of PZT/BFO multilayer thin films

PZT/BFO multilayer thin films were fabricated by the spin-coating method on Pt(200 nm)/Ti(10 nm)/SiO ₂(100 nm)/p-Si(100) substrates using BiFeO3 and Pb(Zr _0.52Ti _0.48)O ₃ metal alkoxide solutions. All PZT/BFO multilayer thin films show the typical XRD pattern of a polycrystalline rhombohedral structure and a uniform and void free grain microstructure. The thickness of the BFO and PZT film by one-cycle of drying/sintering was approximately 40 nm and all films consist of fine grains with a relatively flat surface morphology. PZT/Pt and Pt/Ti interfaces became more and more rough interfacial layers with an increase in the number of coatings because the diffusion of Pb from PZT film into the Pt bottom electrode and the diffusion of Ti was more advanced with an increase in the number of annealing process. All the films showed hysteresis loops with high rectangularity. The remanent polarizations of PZT/BFO and PZT/BFO/PZT multilayer thin films are 47.85 C/cm ² and 39.97 C/cm ², respectively.