Magnetic, Optical, Dielectric, and Sintering Properties Ofnano-Crystalline BaFe0.5Nb0.5O3 Synthesized by Apolymerization Method

J. Mater. Sci. 53 (2018) 1024–1034

29 Pages Posted: 30 Jan 2019

See all articles by Roberto Köferstein

Roberto Köferstein

Martin Luther Universitat Halle Wittenberg

Florian Oehler

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry

Stefan Ebbinghaus

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry

Date Written: September 22, 2017

Abstract

A one-pot polymerization method using citric acid and glucose for the synthesis of nano-crystalline BaFe0.5Nb0.5O3 is described. Phase evolution and the development of the crystallite size during decomposition of the (Ba,Fe,Nb)-gel were examined up to 1100 °C. Calcination at 850 °C of the gel leads to a phase-pure nano-crystalline BaFe0.5Nb0.5O3 powder with a crystallite size of 28 nm. The shrinkage of compacted powders starts at 900 °C. Dense ceramic bodies (relative density ≥ 90%) can be obtained either after conventional sintering above 1250 °C for 1 h or after two-step sintering at 1200 °C. Depending on the sintering regime, the ceramics have average grain sizes between 0.3 and 52 μm. The optical band gap of the nano-sized powder is 2.75(4) eV and decreases to 2.59(2) eV after sintering. Magnetic measurements of ceramics reveal a Neel temperature of about 23 K. A weak spontaneous magnetization might be due to the presence of a secondary phase not detectable by XRD. Dielectric measurements show that the permittivity values increase with decreasing frequency and rising temperature. The highest permittivity values of 10.6 9 104 (RT, 1 kHz) were reached after sintering at 1350 °C for 1 h. Tan δ values of all samples show a maximum at 1–2 MHz at RT. The frequency dependence of the impedance can be well described using a single RC-circuit.

Keywords: Perovskite, BaFe0.5Nb0.5O3, Nano, Decomposition, Permittivity, Magnetism, Band-Gap, Sintering, Ceramic, Densification

Suggested Citation

Köferstein, Roberto and Oehler, Florian and Ebbinghaus, Stefan, Magnetic, Optical, Dielectric, and Sintering Properties Ofnano-Crystalline BaFe0.5Nb0.5O3 Synthesized by Apolymerization Method (September 22, 2017). J. Mater. Sci. 53 (2018) 1024–1034 , Available at SSRN: https://ssrn.com/abstract=3318218

Roberto Köferstein (Contact Author)

Martin Luther Universitat Halle Wittenberg ( email )

Universitätsplatz 10
Halle (Saale), Saxony-Anhalt 06108
Germany

Florian Oehler

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry ( email )

Emil-Abderhalden-Str. 7
Halle an der Saale
06099 Halle (Saale), DE Sachsen-Anhalt 06099
Germany

Stefan Ebbinghaus

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry ( email )

Halle (Saale), Saxony-Anhalt 06108
Germany

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