Solvothermal synthesis of nanocrystalline KTaO.sub.3./sub. : Effect of solvent dielectric constant

0378643 - FZÚ 2013 RIV GB eng J - Journal Article
Makarova, Marina - Bykov, Pavlo - Drahokoupil, Jan - Čerňanský, Marian - Dlabáček, Zdeněk - Dejneka, Alexandr - Jastrabík, Lubomír - Trepakov, Vladimír
Solvothermal synthesis of nanocrystalline KTaO₃ : Effect of solvent dielectric constant.
Materials Research Bulletin. Roč. 47, č. 7 (2012), s. 1798-1773. ISSN 0025-5408. E-ISSN 1873-4227
R&D Projects: GA AV ČR KAN301370701; GA ČR GAP108/12/1941
Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z10100520
Keywords : nanostructures * chemical synthesis * Raman spectroscopy * X-ray diffraction
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 1.913, year: 2012

A set of KTaO3 nanopowders has been prepared at T = 180 oC using various aliphatic alcohols and water as solvents. Pronounced connection between the solvent type and potassium tantalate structures was found. Structural X-ray, TEM and Raman scattering experiments have shown that the solvent dielectric constant ε is an important critical parameter. At ε ~ 24 the cubic perovskite-type phase was formed.Mixed perovskite and pyrochlore phases were formed at larger values of ε. Only pure pyrochlore phase is realized when ε ~ 80. Pyrochlore-free perovskite-structure nanopowder phase formation with the particle size of ~18 and 28 nm was achieved when ethanol and isopropanol solvents were used. Under annealing the coherent domain size decreased down to 6 and 18 nm respectively, since the amorphous phase crystallized. Crystallinity of both as-prepared and annealed powder is the best when isopropanol solvent is used.
Permanent Link: http://hdl.handle.net/11104/0210063