General study on the crystal, electronic and band structures, the morphological characterization, and the magnetic properties of the Sr2DyRuO6 complex perovskite

Abstract

A comprehensive investigation of the general properties of the Sr2DyRuO6 complex perovskite was undertaken. Crystal structure characterization performed by X-ray diffraction measurements and Rietveld analysis allowed establishing that the material crystallizes in a distorted monoclinic perovskite-like structure belonging to the P21/n (#14) space group, with alternating distribution of Dy3+ (2c: 0, 0.5, 0) and Ru5+ (2d: 0.5, 0, 0). Because of the mismatch in the ionic radii, the DyO6 and RuO6 octahedra are forced to tilt around the cubic directions so as to optimize the Sr–O inter-atomic bond lengths. Morphological characterization carried out by scanning electron microscopy indicated a particle size D=37.17nm and an activation energy Q=109.8kJ/mol. Semi-quantitative compositional study, performed through energy-dispersive X-ray experiments, corroborated that the pure phase of the Sr2DyRuO6 was correctly obtained. Magnetic properties determined from the fit of the Curie–Weiss law to the curves of magnetic susceptibility as a function of temperature showed that Sr2DyRuO6 exhibits an antiferromagnetic-like behavior at low temperatures as a consequence of a magnetic transition at T=38K. Data collected with respect to the field dependence of the magnetization showed the existence of a weak ferromagnetic moment relationship with antiferromagnetic-like behavior. Density functional theory allowed establishing the optimum electronic structure for Sr2DyRuO6, and the study of the density of states showed that Dy3+ and Ru5+ are responsible for the magnetic character of the compound, with the prediction that at T=0K it behaves as a half-metallic material. The spin magnetic moment of the cell is close to 16μB, and the integer number of Bohr magneton is a signature of half-metallic character. Evolution of crystal structure at high temperature revealed that Sr2DyRuO6 does not undergo any structural phase transitions, since the Bragg reflections [hkl] do not undergo changes, and the structure is preserved.