Effects of donor W6+-ion doping on the microstructural and multiferroic properties of Aurivillius Bi7Fe3Ti3O21 thin film

Aurivillius phase Bi7Fe3(Ti3 − xWx)O21 + δ (x = 0 and 0.06) thin films were deposited on Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by using a chemical solution deposition method. The W6+-ion doped Bi7Fe3Ti3O21 thin film exhibited tremendous improvements in the electrical and multiferroic properties, namely a low leakage current density, good stability against electrical breakdown, large ferroelectric polarization and large magnetization as compared to the un-doped thin film. The Bi7Fe3(Ti2.94W0.06)O21 + δ thin film was stable against electrical break down at applied electric fields up to 1275 kV/cm, at which the measured remnant polarization (2Pr) and the coercive field (2Ec) values were 33.5 μC/cm2 and 825 kV/cm, respectively whereas, the measured 2Pr value of the un-doped Bi7Fe3Ti3O21 thin film was 3.5 μC/cm2 at an applied electric field of 318 kV/cm. Furthermore, the Bi7Fe3(Ti2.94W0.06)O21 + δ thin film showed a well-saturated ferromagnetic hysteresis loop with large magnetization at room temperature.