Enhanced magnetic properties and leakage current mechanism in bismuth lanthanum ferrite thin films coupled with impedance and magnetic studies

A highly crystalline and pure phase Bi0.993La0.007FeO3 (BLFO) thin films have been grown using a pulsed laser deposition technique. The structural analysis confirmed the thin film is well crystallized with a rhombohedral crystal structure with an R3c space group. The BLFO phase and composition are also confirmed by transmission electron microscopy and EDAX analysis. The surface chemistry of thin films, analysed by X-ray photon spectroscopy, reveals Fe's presence in Fe3+ and Fe2+ states. At RT, the deposited film exhibited high dielectric permittivity (-4 x 102) and low dielectric loss (-10-1). The isothermal magnetization on highly oriented (001)MgO and LaAlO3 (LAO) substrates is investigated. The response is compared to the randomly oriented polycrystalline films on low-cost substrates (Pt/TiO2/SiO2/Si and n-type Si substrate). The enhanced saturation magnetization of 57 emu/cm3 and 36 emu/cm3 at 10 K and 300 K are observed at 2.5 kOe applied field for the film grown on the LAO substrate. Additionally, the low leakage current density of the film is obtained around -1 x 10-7 A/cm2 at a field of 100 kV/cm. Acquiring single-phase BLFO thin films with enhanced electrical and magnetic properties can be relevant in designing multiferroic materials for multiple-state memories, magnetic field sensors, and spintronics applications.

Automated summary

Highly crystalline and pure phase Bi0.993La0.007FeO3 (BLFO) thin films were successfully grown using pulsed laser deposition. The thin film exhibited a rhombohedral crystal structure with an R3c space group. Analysis confirmed the presence of BLFO phase and composition. X-ray photon spectroscopy revealed the presence of Fe in Fe3+ and Fe2+ states. The film showed high dielectric permittivity and low dielectric loss at room temperature, as well as enhanced magnetization and low leakage current density.