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Crystal growth features and properties of layered rare earth and barium cobaltates
Author(s) -
Bychkov G. L.,
Shiryaev S. V.,
Soldatov A. G.,
Shestak A. S.,
Barilo S. N.,
Sheptyakov D. V.,
Conder K.,
Pomjakushina E.,
Podlesnyak A.,
Furrer A.,
Bruetsch R.
Publication year - 2005
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200410356
Subject(s) - liquidus , crystallography , antiferromagnetism , perovskite (structure) , ionic radius , crystallization , phase (matter) , crystal structure , materials science , chemistry , barium , ferromagnetism , analytical chemistry (journal) , ion , inorganic chemistry , condensed matter physics , physics , organic chemistry , chromatography
High quality single crystals of LnBaCo 2 O 5+δ (0 < δ < 1) (Ln = Pr, Eu, Gd, Tb, Dy) with rectangular shape and average dimensions 5 mm × 5 mm × 1 mm were grown for the first time from overstoichiometric flux melt. The data on the primary crystallization field of most cobaltate phases, which appear in parts of corresponding Gibbs triangles in the range 1373 – 1523 K are discussed. Bulk single crystals of new phases HoBaCo 4 O 7 up to 300 mm 3 , YBaCo 4 O 7 and TbBaCo 4 O 7 up to 10 mm 3 in volume were grown first. A solution of these compounds structure has been found in the space group P6 3 mc . For the Ln = Pr, Gd, Sm, Tb, Dy, Ho based systems under the liquidus line there are several other new cobaltate phases of both perovskite, and hexagonal crystal structure. Stability of the double perovskite phase and temperature of the antiferromagnetic – ferromagnetic phase transition in relation to the radius of rare earth ions are compared. The data on the exact analysis of chemical composition, including EDX and iodometric titration, as well as results on magnetic susceptibility of EuBaCo 1‐ x Al x O 5+δ (0 < x < 0.3) are discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)