Structural and magnetic properties of Ruddlesden-Popper compounds in a double-perovskite family Sr_n(Fe,Ta)_nO_(3n)(SrO)

摘要

Sr_3FeTaO_7 and Sr_4FeTaO_8, then =2 and n = 1 member of Ruddlesden-Popper(RP) phases in a double perovskite family Sr_(n+1)(Fe,Ta)_nO_(3n+1), have been synthesized by solid state reaction at 1350 deg C in air. The crystallographic study shows that both compounds adapt typical tetragonal RP structures in the space group I4/mmm with the lattice parameters, a = 3.9650(1) A, c = 20.5560(2) A for Sr_3FeTaO_7 and a = 3.9493(1) A, c = 12.6641(2) A for Sr_4FeTaO_8. Similar to Sr_2FeTaO_6, Fe~(3+) and Ta~(5+) ions are randomly distributed in a single B-site in these structures. At low temperature, both Sr_3FeTaO_7 and SR_4FeTaO_8 exhibit antiferromagnetic interactions, but no long-range magnetic ordering was observed.