Crystal Research and Technology
Cryst. Res. Technol. 40, 395 (2005) - Abstract -

Crystal growth features and properties of layered rare earth and barium cobaltates

G. L. Bychkov, S. V. Shiryaev, A. G. Soldatov, A. S. Shestak, S. N. Barilo, D. V. Sheptyakov*, K. Conder*, E. Pomjakushina*, A. Podlesnyak*, A. Furrer*, and R. Bruetsch**

Institute of Solid State & Semiconductor Physics, BAS, P. Brovka st. 17, Minsk 220072, Belarus
*Laboratory for Neutron Scattering ETH & PSI, 5332 Villigen PSI, Switzerland
**Laboratory for Materials Behaviour, PSI, 5332 Villigen PSI, Switzerland

Keywords single crystal growth, primary crystallization field, cobaltates, phase transition, magnetic transition, phase diagram
PACS 81.10.-h, 81.10.Dn, 81.40.Rs, 61.10.-i, 61.12.Ld
DOI 10.1002/crat.200410356

High quality single crystals of LnBaCo2O5+d (0 < d < 1) (Ln = Pr, Eu, Gd, Tb, Dy) with rectangular shape and average dimensions 5 mm x 5 mm x 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 HoBaCo4O7 up to 300 mm3, YBaCo4O7 and TbBaCo4O7 up to 10 mm3 in volume were grown first. A solution of these compounds structure has been found in the space group P63mc. 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 EuBaCo1-xAlxO5+d (0 < x < 0.3) are discussed.




The full text of this paper in pdf-Format:

If you have come directly to this page, click this symbol to go to the CRT homepage.