Structural chemistry and magnetic properties of the perovskite Sr3Fe2TeO9

AbstractA polycrystalline sample of perovskite-like Sr3Fe2TeO9 has been prepared in a solid-state reaction and studied by a combination of electron microscopy, Mössbauer spectroscopy, magnetometry, X-ray diffraction and neutron diffraction. The majority of the reaction product is shown to be a trigonal phase with a 2:1 ordered arrangement of Fe3+ and Te6+ cations. However, the sample is prone to nano-twinning and tetragonal domains with a different pattern of cation ordering exist within many crystallites. Antiferromagnetic ordering exists in the trigonal phase at 300K and Sr3Fe2TeO9 is thus the first example of a perovskite with 2:1 trigonal cation ordering to show long-range magnetic order. At 300K the antiferromagnetic phase coexists with two paramagnetic phases which show spin-glass behaviour below ~80K