Ceramics-Silikáty 58 (1) 65-69 (2014)

SYNTHESIS AND CHARACTERIZATIONS OF PURE AND DOPED NANOCRYSTALLINE BiFeO₃ CERAMICS BY SHS

The pure and Zn incorporated BiFeO₃ ceramics were synthesized by self-propagating high temperature synthesis (SHS). The X-ray diffractometer (XRD) studies revealed that, both BiFeO₃ and BiFe_0.95Zn_0.05O₃ ceramics crystallizes in a single phase rhombhohedral structure. The room temperature ferroelectric and magnetic hysteresis loop evidenced coexistence of ferroelectricity and magnetism in single phase undoped and Zn doped BiFeO₃. The M-H hysteresis loop of BiFe_0.95Zn_0.05O₃ sample demonstrated a weak ferromagnetism at 300 K and 5 K respectively. The room temperature ferroelectric P-E hysteresis loops of BiFeO₃ and BiFe_0.95Zn_0.05O₃ exhibited an unsaturated behavior and suggests a partial reversal of polarization. A variation of dielectric constant with respect to temperature in BiFeO₃ and BiFe_0.95Zn_0.05O₃ ceramic delivers a dielectric anomaly around 480 and 450°C which is a consequence of antiferromagnetic to paramagnetic phase transition (TN). Moreover, for BiFeO₃ the anomaly manifests a possible coupling between electric and magnetic dipole moments.

Keywords: BiFeO₃ Ceramics, SHS, XRD, Ferroelectrics, Multiferroics, Dielectrics