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

Journal Article · Tue May 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.03.002· OSTI ID:21015812

Pinacca, R M ^[1]; Viola, M C ^[1]; Pedregosa, J C ^[1]; Martinez-Lope, M J ^[2]; Carbonio, R E ^[3]

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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)

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 the 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.

• OSTI ID: 21015812
• Journal Information: Journal of Solid State Chemistry, Vol. 180, 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); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

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