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Title: Preparation, crystal structure and magnetic behavior of new double perovskites Sr{sub 2} B'UO{sub 6} with B'=Mn, Fe, Ni, Zn

Sr{sub 2} B'UO{sub 6} double perovskites with B'=Mn, Fe, Ni, Zn have been prepared in polycrystalline form by solid-state reaction, in air or reducing conditions. These new materials have been studied by X-ray diffraction (XRD), magnetic susceptibility and magnetization measurements. The room-temperature crystal structure is monoclinic (space group P2{sub 1}/n), and contains alternating B'O{sub 6} and UO{sub 6} octahedra sharing corners, tilted along the three pseudocubic axes according to the Glazer notation a {sup -} a {sup -} b {sup +}. The magnetic measurements show a spontaneous magnetic ordering below T {sub N}=21 K for B'=Mn, Ni, and T {sub C}=150 K for B'=Fe. From a Curie-Weiss fit, the effective paramagnetic moment for B'=Mn (5.74 {mu}{sub B}/f.u.) and B'=Ni(3.51 {mu}{sub B}/f.u.) are significantly different from the corresponding spin-only moments for the divalent cations, suggesting the possibility of a partial charge disproportionation B'{sup 2+}+U {sup 6+}{r_reversible}B'{sup 3+}+U {sup 5+}, also accounting for plausible ferrimagnetic interactions between B' and U sublattices. The strong curvature of the reciprocal susceptibility for B'=Fe precludes a Curie-Weiss fit but also suggests the presence of ferrimagnetic interactions in this compound. This charge disproportionation effect is also supported by the observed B'-O distances, which are closer to themore » expected values for high-spin, trivalent Mn, Fe and Ni cations. - Graphical abstract: The title double perovskites are monoclinic, space group P2{sub 1}/n, and the magnetic properties suggest the possibility of a partial charge disproportionation B'{sup 2+}+U {sup 6+}{r_reversible}B'{sup 3+}+U {sup 5+}, accounting for plausible ferrimagnetic interactions between B' and U sublattices.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Area de Quimica General e Inorganica 'Dr. Gabino F. Puelles', Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700-San Luis (Argentina)
  2. Instituto de Ciencias de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)
  3. INFIQC, Departamento de Fisicoquimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)
  4. Instituto de Ciencias de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain), E-mail: ja.alonso@icmm.csic.es
Publication Date:
OSTI Identifier:
21015812
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 5; Other Information: DOI: 10.1016/j.jssc.2007.03.002; PII: S0022-4596(07)00099-0; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CUBIC LATTICES; FERRIMAGNETISM; IRON COMPOUNDS; MAGNETIC SUSCEPTIBILITY; MAGNETIZATION; MANGANESE COMPOUNDS; MONOCLINIC LATTICES; NICKEL COMPOUNDS; OXIDATION; OXIDES; PARAMAGNETISM; PEROVSKITES; POLYCRYSTALS; REDUCTION; SPACE GROUPS; SPIN; STRONTIUM COMPOUNDS; TEMPERATURE RANGE 0273-0400 K; URANIUM COMPOUNDS; X-RAY DIFFRACTION; ZINC COMPOUNDS