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

TL;DR

This study reports the fabrication of BiFeO3-PbTiO3 thin films with a monoclinic phase using a multilayer chemical deposition method, exhibiting strong ferroelectric properties and domain structures confirmed by microscopy and electrical measurements.

Contribution

It introduces a multilayer chemical solution deposition technique to produce monoclinic BiFeO3-PbTiO3 films with enhanced ferroelectric properties, differing from the typical tetragonal phase.

Findings

Monoclinic M_A phase observed in BF-PT films.

Films exhibit ferroelectric switching confirmed by piezo-force microscopy.

High remanent polarization of up to 18 μC/cm^2 with low leakage currents.

Abstract

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.