Abstract:
The work investigated the crystal structure of the double perovskite Ba₂GdRuO₆ by X-ray
powder diffraction. X-ray phase analysis was performed, which confirmed the single-phase nature
of the sample. Using the TREOR module of the HighScore Plus 3.0 program, the diffraction pattern
was indexed and the space symmetry group I41/amd (141) of the tetragonal system with unit cell
parameters a=b=2.478 Å, c=11.897 Å was determined. The microstructural parameters of the crystal
lattice were refined using the Rietveld method using correlation matrices. The discrepancy factor is
R=3.93%, which indicates the high quality of the structural model. The coordinates of the Ba, Gd,
Ru, and O atoms in the structure were established, their Wyckoff positions and filling factors were
determined. It is shown that the structure is a typical double perovskite A₂BB'O₆, where gadolinium
(Gd³⁺) and ruthenium (Ru⁵⁺) atoms form regular octahedra with six oxygen atoms each, located in
positions 8c and 8d, respectively, with a coordination number Z=6. Barium atoms occupy large
cavities between the octahedra, and oxygen forms intermetallic bridges, ensuring the coherence
of the structure. This structure is typical of materials with magnetic and electrical properties that
are interesting for materials physics. Literature data on the magnetic, electronic, mechanical, and
thermoelectric properties of Ba₂GdRuO₆ are analyzed. The material exhibits complex magnetic
behavior with competition of antiferromagnetic and ferrimagnetic phases, a Curie temperature of
60 K, is a semiconductor with a band gap of about 1 eV, and exhibits high thermoelectric efficiency
at elevated temperatures. The proposed crystal structure for the compound Ba2GdRuO6 can be
determined in further studies using the diffraction spectrum recorded by the powder method with
the Bragg-Brentano imaging geometry in a wider range. It is also possible to synthesize a single
crystal of this compound and study the crystal structure by the single crystal method.
