Investigations of nano-crystalline Sr0.5Ba0.5Nb2O6 and bulk ceramics synthesized by a polymerization method using PEG400

Abstract

Nano-crystalline Sr 0.5 Ba 0.5 Nb 2 O 6 was synthesized by a one-pot method using PEG400 and citric acid. Calcination of the (Sr,Ba,Nb)-gel at 600 °C leads to Sr 0.5 Ba 0.5 Nb 2 O 6 with a crystallite size of 24(2) nm and a specific surface area of 38.5(10) m 2 g 1. Sintering up to 1325 °C leads to ceramics with globular or irregular-shaped grains and average grain sizes between 1.3 and 2.4 µm, whereas higher temperatures lead to a rod-like microstructure. The indirect allowed optical band gap varies between 3.70(5) and 3.29(5) eV. Dielectric measurements show a diffuse phase transition and weak relaxor properties. The maximum of the permittivity occurs between 116 and 147 °C. The frequency dependence of the impedance can be well described by one or two RC-circuits depending on sintering temperature. The 2 melting temperature is determined as 1506(7) °C with H f = 140(20) kJ mol 1. The average linear thermal expansion coefficient is found to be 10.5(5)10 6 K 1 .

Synthesis, structural characterization and functional properties of Sr0.5Ba0.5Nb2−xFexO6 ceramic powders

“…The Table 1 contains the parameters confirming the monophasic powders. The monophasic sample was obtained at lower temperature and less calcination time than reported by Köferstein [6] . The TEM micrograph for the Sr0.5Ba0.5Nb1.98Fe0.02O6 sample with Sr/Ba = 0.5/0.55 and pH=10 (Fig.…”

“…Therefore, the doping of SBN compound with iron results in the multiferroic property. Several methods have been proposed for the synthesis and processing of SBN ferroelectric ceramics, including solidstate synthesis, gel citrate, Pechini and controlled precipitation [4][5][6][7][8][9][10] . The controlled precipitation method is based on aqueous media reactions containing stoichiometric predetermined amounts of the precursors (salts).…”

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

“…With rising strontium content an increasing relaxor behavior can be observed [12]. For Sr 0.5 Ba 0.5 Nb 2 O 6 , the permittivity maximum (T m ), which reflects the ferroelectric ⇆ paraelectric phase transition, is between 110 and 130 C for single crystals [3,11], while for polycrystalline samples values between 40 and 177 C have been reported [13][14][15][16][17].…”

“…Usually, Sr 0.5 Ba 0.5 Nb 2 O 6 is synthesized by the conventional mixedoxide method which leads to coarse-grained powders. Additionally, few soft-chemistry syntheses have been reported to produce sub-micro or nano-sized powders [14,[18][19][20][21]. Compacts of strontium barium niobate reveal moderate densification behaviour.…”

Enhanced Piezocatalytic Activity of Sr0.5Ba0.5Nb2O6 Nanostructures by Engineering Surface Oxygen Vacancies and Self-Generated Heterojunctions

“…In recent years, lead-free oxides with tungsten–bronze (TB) structures have attracted widespread attention because of their outstanding pyroelectric, piezoelectric, electro-optic, and photorefractive properties, − demonstrating promising potential applications in the fields of optics and electronics. Among them, Sr 0.5 Ba 0.5 Nb 2 O 6 (SBN), which belongs to the P 4 bm space group, possesses superior piezoelectric and pyroelectric properties. ,− In SBN, only 180° ferroelectric polarization domains can be formed, making it highly suitable for separating and transporting electrons and holes in opposite directions . The unique domain structures and exceptional piezoelectric properties make lead-free SBN materials promising candidates for use in mechanical force-induced catalytic applications.…”