Investigations of BaFe0.5Nb0.5O3 nano powders prepared by a low temperature aqueous synthesis and resulting ceramics. Issue 4 (April 2017) - Köferstein, Roberto
Abstract: A facile method to prepare nanoscaled BaFe0.5 Nb0.5 O3 via synthesis in boiling NaOH solution is described herein. The nano-crystalline powder has a high specific surface area of 55 m 2 g −1 and a crystallite size of 15 nm. The as-prepared powder does not show any significant crystallite growth up to 700 °C. The activation energy of the crystallite growth process was calculated as 590 kJ mol −1 . Dense ceramics can be obtained either after sintering at 1200 °C for 1 h or after two-step sintering at 1000 °C for 10 h. The average grain sizes of ceramic bodies can be tuned between 0.23 μm and 12 μm. The thermal expansion coefficient was determined as 11.4(3)·10 −6 K −1 . The optical band gap varies between 2.90(5) and 2.63(3) eV. Magnetic measurements gave a Néel temperature of 20 K. Depending on the sintering regime, the ceramic samples reach permittivity values between 2800 and 137, 000 at RT and 1 kHz.