Structural and dielectric properties of lead free BiFeO3/NiFe2O4 multiferroic heterostructures

Multiferroic nanocrystalline ceramics of Bismuth ferrite (BiFeO3) and nickel ferrite (NiFe2O4) were synthesised via sol- gel auto combustion technique using organometallic precursors. An equimolar amount of bismuth ferrite (BFO) and nickel ferrite (NFO) were pressurised in bi-layer (BFO-NFO) and tri-layer (BFO-NFO-BFO) by giving a pressure of about 100 kg/cm2 using a hydraulic pellet press. X-ray Diffractometer (XRD) was employed to analyse the structural properties in relation to the resulting heterostructures. Scanning Electron Microscopy (SEM) was used to examine the cross-sectional micrograph of the heterostructures. The dielectric properties were measured using LCR meter and corresponding dielectric constant data was fitted with Cole-Cole equation to decipher the nature of dielectric relaxation. Impedance analysis was carried out at elevated temperature in the frequency range of 100 Hz–1 MHz and fitted with equivalent circuit model. We could observe slight enhancement in the electrical properties in tri-layer heterostructure as compared to the bilayer structure.