Tailoring Bi1-x-yBaxFeyFeO₃ for desired properties: insights into structural, dielectric, and magnetic responses

In present study, samples of Bi 1−x−y Ba x Fe y FeO 3 have been synthesized, where x = 0.15, y = 0; x = 0.10, y = 0.10; and x = 0.15, y = 0.10 utilizing a swift two-stage solid-state reaction method. X-ray diffraction (XRD) data has been Rietveld refined to evaluate the structural parameters. Micro-strain is also calculated using Williamson Hall method. Temperature (300 K to 660 K) dependent measurements of the dielectric constant have been conducted at various frequencies (100 kHz, 500 kHz, and 1000 kHz). The dielectric constant ( ε ′) rises as the temperature increases. Two dielectric anomalies around 450 K and 613 K have been noticed in ε ′ versus T curves for all the samples which might be related with defect dipoles and the magnetic transition respectively. Further, an insignificant value of loss tangent (0.2) specifically at around 300 K is a signal of small leakage current in the samples. The source of high dielectric constant is discussed by considering the structural distortions in the ceramics. A clear hysteresis loop has been observed for all the samples which is a sign of collapse of antiferromagnetic nature of BiFeO 3. Further, in case of co-doped samples, almost a saturation in magnetization with magnetization value 5.9718 emu g −1 has been noticed in hysteresis curve indicating a major contribution of ferromagnetic interaction. Enhancement in the net magnetization is briefly discussed by considering the ferromagnetic type direct interaction among Fe 3+ ions and suppressing the anti-ferromagnetic type super exchange interaction.