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Titre du document / Document title

Perovskite and pyrochlore modifications of Pb2MnReO6: Synthesis, structure, and electronic properties

Auteur(s) / Author(s)

RAMESHA K. (1) ; SEBASTIAN L. (2) ; EICHHORN B. (1) ; GOPALAKRISHNAN J. (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Chemistry and Biochemistry, Center for Superconductivity Research, University of Maryland, College Park, Maryland 20742, ETATS-UNIS
(2) Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, INDE

Résumé / Abstract

We describe the synthesis and investigations of Pb2MnReO6 in perovskite and pyrochlore modifications. Both the modifications are formed at atmospheric pressure, the perovskite (I) at 550 °C and the pyrochlore (II) at 600 °C. Rietveld refinements of the structures using the powder XRD data show that oxide I adopts the monoclinic (P21/n) double perovskite structure with partial ordering (∼72%) of MnII/ReVI at the octahedral sites, while oxide II crystallizes in a defect-pyrochlore structure where MnII/ReVI are disordered at the octahedral sites. The frustrated cation sublattice precludes a long-range ordering of Mn/Re in the pyrochlore structure. I is a semiconductor showing evidence for a ferrimagnetic ordering at Tc ∼ 100 K, but the small saturation magnetic moment (<S> = 0.81) and the divergence between FC and ZFC magnetization data are consistent with spin-glass-like behavior and a partially ordered Mn/Re in the double perovskite structure. On the other hand, both the Curie-Weiss paramagnetism down to ∼5 K and non-Arrhenius electrical resistivity behavior of II suggest a spin-liquid/spin-glass ground state that is consistent with the frustrated cation sublattice of the pyrochlore structure.

Revue / Journal Title

Chemistry of materials    ISSN  0897-4756 

Source / Source

2003, vol. 15, no3, pp. 668-674 [7 page(s) (article)] (20 ref.)

Langue / Language

Anglais

Editeur / Publisher

American Chemical Society, Washington, DC, ETATS-UNIS  (1989) (Revue)

Mots-clés anglais / English Keywords

Magnetic properties

;

Electrical properties

;

Transition element compounds

;

Oxides

;

Inorganic compounds

;

Magnetic susceptibility

;

Electrical conductivity

;

Magnetic moments

;

Magnetization

;

Magnetic ordering

;

Semiconductor materials

;

Rhenium oxides

;

Manganese oxides

;

Lead oxides

;

Pyrochlore type compound

;

Perovskites

;

Crystal structure

;

XRD

;

Chemical reactions

;

Chemical preparation

;

Experimental study

;

Mots-clés français / French Keywords

Propriété magnétique

;

Propriété électrique

;

Métal transition composé

;

Oxyde

;

Composé minéral

;

Mn O Pb Re

;

Pb2MnReO6

;

Susceptibilité magnétique

;

Conductivité électrique

;

Moment magnétique

;

Aimantation

;

Ordre magnétique

;

Semiconducteur

;

Rhénium oxyde

;

Manganèse oxyde

;

Plomb oxyde

;

Pyrochlores

;

Perovskites

;

Structure cristalline

;

Diffraction RX

;

Réaction chimique

;

Préparation chimique

;

Etude expérimentale

;

Mots-clés espagnols / Spanish Keywords

Pirocloros

;

Localisation / Location

INIST-CNRS, Cote INIST : 21957, 35400010394303.0120

Nº notice refdoc (ud4) : 14526715



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