Abstract
In this paper, major reduction in sintering time,temperautre and significant improvement over final density of sitnered sample is reported for the microwave sintered nanocrystalline BiFeO3 (BFO) ceramic. Also, different sintering time and temperatures have been used to tailor the grain size and the final density of the resulting BFO ceramics synthesized from phase pure BFO nanoparticles (d̄ ≈10 nm). Microwave sintering resulted in reducing the sintering time substantially (by 1h), and has resulted in submicron sized grains and high resistivity ∼1.8 GΩ-cm. The AC conductivity is seen to follow the Jonscher’s power law behavior, suggesting correlated barrier hopping (CBH) mechanism in the sample. The role of oxygen vacancies at high temperature, due to volatility of bismuth, in dielectric and conductivity behavior is also discussed. Further, the sample displayed dielectric anomaly near magnetic transition temperature (∼180 °C) indicating bearing of magnetic moments on the dielectric properties. Using Impedance Spectroscopy (IS) we have established, the electrical heterogeneity of the ceramic BFO reavealing semiconducting nature of grains and insulating nature of grain boundary. This, formation of network of insulating grain boundaries and semiconducting grains could lead to formation of internal barrier layer capacitance (IBLC) leading to high dielectric constant in microwave sintered BFO.
Highlights
Multiferroic materials have been widely investigated in the past decade due to simultaneous exhibition of multiple ferroic properties such as ferroelectricity, ferromagnetism and ferroelasticity.BiFeO3 (BFO) is the most widely investigated material possibly due to the exhibition of multiferroic behavior at room temperature.[1]
We have revealed through impedance spectroscopy that electrical microstructure of microwave sintered
BiFeO3 ceramics is electrically heterogeneous with semiconducting grains and insulating grain boundaries; this could lead to internal barrier layer capacitance (IBLC) in the sample which might be held responsible for high εr′ in microwave sintered, fine grained, nanocrystalline BiFeO3 apart from other extrinsic effects
Summary
Multiferroic materials have been widely investigated in the past decade due to simultaneous exhibition of multiple ferroic properties such as ferroelectricity, ferromagnetism and ferroelasticity. Been synthesized by using microwave sintering method due to advantages such as, high heating rates of microwave sintering, prominently shortening of the processing time and temperature as compared to conventional sintering techniques.[23,24,25,26,27,28,29] Considering the plausible reduction in sintering time and temperature, probability of bismuth loss could be minimized, which in turn could prove advantageous to the electrical properties of BiFeO3. BiFeO3 ceramics is electrically heterogeneous with semiconducting grains and insulating grain boundaries; this could lead to internal barrier layer capacitance (IBLC) in the sample which might be held responsible for high εr′ in microwave sintered, fine grained, nanocrystalline BiFeO3 apart from other extrinsic effects
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
