Effects of Nd-doping on the structural, electrical, and multiferroic properties of Bi7Fe3Ti3O21 thin films

Aurivillius-phase six-layered Bi7Fe3Ti3O21 (BFTO21) and Nd-doped Bi6.4Nd0.6Fe3Ti3O21 (BNdFTO21) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method in order to investigate their structural, electrical, and multiferroic properties. Doping the Bi sites of the BFTO21 with Nd-ions led to remarkable improvements in the electrical and the multiferroic properties. The electrical study of the BNdFTO21 thin film showed a low leakage current density of 4.38 × 10-6 A/cm at an applied electric field of 100 kV/cm, which was about one order of magnitude lower than that of the BFTO21 thin film. The ferroelectric P - E hysteresis loop of the BNdFTO21 thin film exhibited a large remnant polarization (2Pr) of 24 μC/cm2 and a low coercive electric field (2Ec) of 154 kV/cm at an applied electric field of 239 kV/cm. Furthermore, the magnetization and the coercive magnetic field that were observed for the BNdFTO21 thin film at room temperature were drastically enhanced compared to those observed for the BFTO21 thin film