Heavy-rare-earth-induced structural and magnetic properties in (Sr2-xLnx)FeMoO6 (Ln = Sr, Gd, Tb, Dy , Y and Ho) double perovskite

Abstract Heavy-rare-earth-doped (HR-doped) (Sr 2-x Ln x )FeMoO 6 (x = 0, 0.1 and 0.15, Ln = Sr, Gd, Tb, Dy, Y and Ho) have been synthesized by solid-state reaction. Crystal structure, magnetic and transport properties of the compound are investigated systematically. Structural refinement shows that although all the compounds belong to the same space group, I 4/ m , prominent structural distortion is introduced: all the compounds seem to be divided into two groups: for (Sr 2-x Gd x )FeMoO 6 and (Sr 2-x Tb x )FeMoO 6 compounds, FeO 6 octahedra becomes expansive and MoO 6 octahedra becomes contractive, while FeO 6 octahedra is compressed and MoO 6 octahedra is stretched for the other compounds. Owing to the competing interaction between structural distortion and electron doping, T C of (Sr 2-x Gd x )FeMoO 6 and (Sr 2-x Tb x )FeMoO 6 is increased, resistivity is decreased and metallic behavior is enhanced, while the reverse occurs to the other compounds. Saturation magnetization of (Sr 2-x Ln x )FeMoO 6 suggests that the long-range-ordered-moments of Gd 3+ , Tb 3+ , Dy 3+ and Ho 3+ maybe parallel with that of Fe 3+ spin at low temperature, which is the same as La-, Ce-, Pr-, Nd- and Sm-doped case. Above results reveal that rare earth elements (La-Ho, except for Eu) exhibit the same coupling effect with Sr 2 FeMoO 6 , despite of their different magnetic nature. Our investigation offer comprehensive knowledge on the structural and magnetic properties of rare-earth-doped Sr 2 FeMoO 6 .