Synthesis, structural characterization and magnetic properties of the monoclinic ordered double perovskites BaLaMSbO6, with M = Mn, Co and Ni

M.C. BLANCO; J.M.DEPAOLI; S.A. CEPPI; TIRAO, G.; V.M. NASSIF; J. GUIMPEL; R. CARBONIO

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2014 vol. 606 p. 139 - 148

0925-8388

Double perovskites BaLaMnSbO6, BaLaCoSbO6 and BaLaNiSbO6, weresynthesized by conventional ceramic method in air, as polycrystallinepowders. The Mn and Ni compounds belong to the I 2/m monoclinic spacegroup, while the Co perovskite belongs to the I 4/m tetragonal spacegroup. Effective presence of Mn2+ has been well established by X-rayemission spectroscopy for BaLaMnSbO6, and there is no evidence of Mn3+.BaLaCoSbO6 and BaLaNiSbO6 only show the expected 3D-antiferromagneticbehaviour typical of super-superexchange interactions, while BaLaMnSbO6displays signs of superparamagnetism in the 40-160 K range, which arisesfrom unbalanced antiferromagnetism inside nanoclusters formed by regionswhich are rich in Mn2+ ― O2- Mn2+ paths. Neutron powder diffraction datafor BaLaMnSbO6 reveals that at 3 K, only long range orderantiferromagnetic arrangement of Mn2+ spins on 2d octahedral sites isobtained.