Effect of insertion of low leakage polar layer on leakage current and multiferroic properties of BiFeO3/BaTiO3 multilayer structure

Abstract

Polycrystalline BiFeO₃ is a well established leaky room temperature multiferroic material. The present work focuses on the realization of high end functionalities such as polarization, low leakage current and high magnetization in a sandwich structure of BaTiO₃ and BiFeO₃. Interestingly, it was found that the BaTiO₃ barrier layer effectively reduces the leakage current which in turn significantly improves the ferroelectric and ferromagnetic properties. The increase in the number of BaTiO₃ barrier layers stops the charge carriers for long range mobility. X-ray diffraction (XRD) analysis suggests that an increase in the number of BaTiO₃ layers significantly increases the stress modulus in the both the constituent layers along c-axis and tetragonality in the BiFeO₃ films which helps in improving the multiferroic properties in multilayered structure. The saturation polarization (P_s) and magnetization (M_s) significantly increased from 18 to 99 μC cm⁻² and 28 to 95 emu cm⁻³ respectively with increase in number of barrier layers from 2 to 6. The BiFeO₃/BaTiO₃ multilayered structure with enhanced multiferroic properties finds potential application in the tunable devices.