Cationic ordering and role of the B-site lanthanide(III) and molybdenum(V) cations on the structure and magnetism of double perovskites Sr 2 LnMoO 6

R.M. PINACA; S.A. LARRÉGOLA; C.A. LÓPEZ; J.C. PEDREGOSA; VLADIMIR POMJAKUSHIN; R.D. SÁNCHEZ; J.A. ALONSO

MATERIALS RESEARCH BULLETIN

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2015 vol. 66 p. 192 - 199

0025-5408

We describe the preparation, crystal structure determination and magnetic properties of a new series of ordered double perovskite oxides Sr 2 LnMoO 6 (Ln = Eu, Gd, Dy, Ho, Er, Yb) with Mo 5+ and Ln 3+ electronic configurations. These compounds have been obtained by solid state reaction under reducing conditions in order to stabilize Mo 5+ cations. Structural characterization by XRPD and NPD was performed when Ln = Ho, Er, Yb and just XRPD for absorbing Ln = Eu, Gd, Dy. At room temperature, an excellent Rietveld fit was obtained for all the samples in a monoclinic symmetry, space group P2 1 /n, with long-range ordering of Ln and Mo atoms. Magnetic susceptibility measurements show that some of these materials present magnetic ordering below 25 K and the determined effective magnetic moments are consistent with thoseexpected for the pair Ln 3+ ?Mo 5+ . All the phases have negative values of the Weiss temperature indicating dominance of antiferromagnetic interactions.