| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1490581 | Materials Research Bulletin | 2011 | 6 Pages |
The crystal structure behavior of the Sr2GdRuO6 complex perovskite at high-temperature has been investigated over a wide temperature range between 298 K ≤ T ≤ 1273 K. Measurements of X-ray diffraction at room-temperature and Rietveld analysis of the experimental patterns show that this compound crystallizes in a monoclinic perovskite-like structure, which belongs to the P21/n (#14) space group and 1:1 ordered arrangement of Ru5+ and Gd3+ cations over the six-coordinate M sites. Experimental lattice parameters were obtained to be a =5.8103(5) Å, b =5.8234(1) Å, c =8.2193(9) Å, V = 278.11(2) Å3 and angle β = 90.310(5)°. The high-temperature analysis shows the occurrence of two-phase transitions on this material. First, at 573 K it adopts a monoclinic perovskite-type structure with I2/m (#12) space group with lattice parameters a = 5.8275(6) Å, b = 5.8326(3) Å, c = 8.2449(2) Å, V = 280.31(3) Å3 and angle β = 90.251(3)°. Close to 1273 K it undergoes a complete phase-transition from monoclinic I2/m (#12) to tetragonal I4/m (#87), with lattice parameters a = 5.8726(1) Å, c = 8.3051(4) Å, V = 286.39(8) Å3 and angle β = 90.0°. The high-temperature phase transition from monoclinic I2/m (#12) to tetragonal I4/m (#87) is characterized by strongly anisotropic displacements of the anions.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Crystal structure, thermal expansion and phase transitions at high-temperature of Sr2GdRuO6 perovskite has been investigated. ► X-ray diffraction pattern at 298 K of Sr2GdRuO6 corresponds to monoclinic perovskite-type structure with P21/n space group. ► Evolution of X-ray diffraction patterns at high-temperature shows that the Sr2GdRuO6 perovskite suffers two-phase transitions. ► At 573 K the X-ray diffraction pattern of Sr2GdRuO6 corresponds to monoclinic perovskite-type structure with I2/m space group. ► At 1273 K the Sr2GdRuO6 perovskite suffers a complete phase-transition from monoclinic I2/m (#12) to tetragonal I4/m (#87).
