Cationic ordering and role of the B-site lanthanide (III) and molybdenum (V) cations on the structure and magnetism of double perovskites Sr2LnMoO6

R.M. PINACCA; S.A. LARRÉGOLA; C.A. LOPEZ; V. POMJAKUSHIN; R.D. SÁNCHEZ; J.A. ALONSO

MATERIALS RESEARCH BULLETIN

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; 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 Sr2LnMoO6 (Ln = Eu, Gd, Dy, Ho, Er, Yb) with Mo5+ and Ln3+ electronic configurations. These compounds have been obtained by solid state reaction under reducing conditions in order to stabilize Mo5+ 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 P21/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 those expected for the pair Ln3+-Mo5+. All the phases have negative values of the Weiss temperature indicating dominance of antiferromagnetic interactions.