A comparative study of structural and multiferroic properties of Ca, Sr and Ba doped 0.2BiFeO3–0.8PbTiO3 solid solutions

A comparative study of structural, ferroelectric, magnetic and dielectric properties of Ca, Sr and Ba doped 0.2BiFeO3–0.8PbTiO3 (BF-PT) binary solid solutions synthesized via the solid-state reaction route has been reported. The XRD analysis confirms that all the samples possess a tetragonal structure and, after the BF-PT system, the maximum c/a ratio of ~1.070 has been observed in the BF-PCT system. The remnant polarization (Pr ~ 1.99μC/cm2) and the dielectric constant (~563 at 3 MHz) have also been observed to be the highest in the BF-PCT system as compared to BF-PST and BF-PBT solid solutions. The AC conductivity data of all the prepared samples obey Universal Joncher's Power law and was found to be increased from the BF-PT system to the BF-BT system. A simultaneous change in the hopping mechanism has also been observed from a translational type in the Pb-based system to a localized type in the Ba-based (non‑lead) system. The NEXAFS study reveals that the best dielectric and ferroelectric results observed in the lead-based solid solutions have been attributed to the strong hybridization between the Pb 6 s and O 2p states of PbTiO3, which are absent in BaTiO3.