Structural Changes and Ferroelectric Properties of BiFeO₃-PbTiO₃ Thin Films Grown via a Chemical Multilayer Deposition Method

Thin films of (1-x)BiFeO₃-xPbTiO₃ (BF-xPT) with x ~ 0.60 were fabricated on Pt/Si substrates by chemical solution deposition of precursor BF and PT layers alternately in three different multilayer configurations. These multilayer deposited precursor films upon annealing at 700{\deg}C in nitrogen show pure perovskite phase formation. In contrast to the equilibrium tetragonal structure for the overall molar composition of BF:PT::40:60, we find monoclinic structured BF-xPT phase of M_A type. Piezo-force microscopy confirmed ferroelectric switching in the films and revealed different normal and lateral domain distributions in the samples. Room temperature electrical measurements show good quality ferroelectric hysteresis loops with remanent polarization, Pr, of up to 18 {\mu}C/cm² and leakage currents as low as 10^-7 A/cm².