The effect of the B-site cation and oxygen stoichiometry on the local and average crystal and magnetic structures of Sr 2 Fe 1.9 M 0.1 O 5+y (M = Mn, Cr, Co; y = 0, 0.5)

Six compounds with formula Sr2Fe1.9M0.1O5+y (M = Mn, Cr, Co; y = 0, 0.5) were synthesized in air and argon, exhibiting surprisingly different properties depending on the B-cation type in spite of the low (5%) doping level. All argon synthesized phases, y 0, have long range brownmillerite ordering of oxygen vacancies with Icmm symmetry as shown by neutron diffraction (ND). All show long-range G-type antiferromagnetic order with Néel …