Effects of cobalt substitution for iron in PbBaFe _2-x Co _x O ₅ (x = 0, 0.25)

Abstract We report on a new series of polycrystalline perovskite-related compounds from the A n B n O 3n-2 homologous series with general formula PbBaFe 2-x Co x O 5 (x = 0, 0.25, 0.5, 0.75, 1). The compounds were successfully synthesized by employing a modified solution-combustion technique. An additional experimental information was obtained by neutron diffraction, confirming that the studied compounds crystallize in the orthorhombic space group Pnma and are isostructural with the end member PbBaFe 2 O 5 . At 300 K, an antiferromagnetic (AFM) structure with a propagation vector k = (0, ½, ½) was determined to develop in both undoped PbBaFe 2 O 5 and low-doped PbBaFe 1.75 Co 0.25 O 5 . For the low doped composition, the saturated effective magnetic (Fe,Co) moment at T=10 K was refined to M s =4.05±0.02 μ B and the antiferromagnetic transition temperature was estimated as T N =561±10 K.