Properties of the n=3 Ruddlesden-Popper phases Sr4Mn3-xFexO10-δ (x=1, 1.5, 2)

We have prepared a series of Fe-substituted Sr4Mn3-x FexO10-delta strontium manganates with x = 1, 3/2, and 2, These compounds adopt the n = 3 Ruddlesden-Popper structure (I4/mmm), unlike the parent compound Sr4Mn3O10, which contains a network of face-sharing MnO6 octahedra, with the larger Fe ion preferentially occupying the Mn/Fe (1) middle layer of the corner-sharing trioctahedra slabs, We have investigated their physical properties with X-ray diffraction, X-ray absorption near edge spectroscopy, Mossbauer spectroscopy, variable temperature resistivity, and magnetic susceptibility. In addition, for the x = 2 compound we preformed room temperature neutron diffraction experiments, These compounds need to be formed at high temperatures; as a consequence they are oxygen deficient and contain some Fe3+, They are insulators and exhibit spin-glass-like transitions at low temperature. (C) 2000 Academic Press.