Dielectric and magnetic response of BiFeO₃ in the presence of ionic filler at room temperature

Composite systems consisting of ionic sodium chloride (NaCl) as a filler with varying weight percentages (x = 0%, 10%, 30%, and 50%) embedded into the matrix of multiferroic bismuth ferrite (BiFeO₃) were synthesized. Post-annealed at 750 °C, the XRD analysis reveals that the presence of NaCl leads to the formation of secondary phases. The particle grain size varies in the range of 0.5–1.5 μm as found from FESEM. The VSM study shows the coercive field (Hc) enhancement with maximum H_c = 79.18 Oe is found for the composite system x = 10%. The electrical impedance study reveals that at a low-frequency regime, the real component of dielectric permittivity has relatively increased for the composite systems compared to as-prepared bismuth ferrite (BFO). The dielectric loss increases at low frequency but remains comparable at the high-frequency limit, indicating a possible role in the energy storage application. Exponent (n) for frequency-dependent electrical conductivity is found to be large (n > 1) which is due to various degrees of the proximity of adjacent NaCl grains distributed in a multiferroic matrix.