hide
Free keywords:
-
Abstract:
Powder neutron diffraction data on spin ladder compounds SrFe(2)Ch(2)O (Ch = S, Se) indicate that their magnetic ground states feature long-range antiferromagnetic spin ordering with k = [0,0,0]. The superexchange interaction is antiferromagnetic across each rung via oxygen but ferromagnetic along the ladders via Ch. At 10 K, the ordered spins point towards the center of the ladders but are faintly canted away from a collinear state. The sizes of the ordered moments are 3.3 and 3.5 mu(B) Fe-1 for SrFe2S2O and SrFe2Se2O, respectively. The polar, heteroleptic, tetrahedral FeCh(3)O coordination suggests an angle of 8 degrees between the local structure polarity and the magnetic moment spin orientation. Mossbauer spectroscopic data confirm the magnetic ordering scenario and indicate that the local Fe-O bond rules the electric field gradient at the Fe-site.
