Synthesis, Structural Characterization, and Physical Properties of the Early Rare-Earth Metal Digermanides REGe2–x (x ≈ 1/4) [RE = La–Nd, Sm]. A Case Study of Commensurately and Incommensurately Modulated Structures

Rare-earth metal germanides with the general formula RE 4Ge7 (RE = La, Ce, Pr, Nd, Sm) have been synthesized using the In-flux technique. Their structures have been established from single-crystal and powder X-ray diffraction, and the structural elucidation has been aided by electron diffraction. Th...

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Bibliographic Details
Published in:Inorganic chemistry 2013-01, Vol.52 (2), p.953-964
Main Authors: Zhang, Jiliang, Tobash, Paul H, Pryz, William D, Buttey, Douglas J, Hur, Namjung, Thompson, Joe D, Sarrao, John L, Bobev, Svilen
Format: Article
Language:English
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Summary:Rare-earth metal germanides with the general formula RE 4Ge7 (RE = La, Ce, Pr, Nd, Sm) have been synthesized using the In-flux technique. Their structures have been established from single-crystal and powder X-ray diffraction, and the structural elucidation has been aided by electron diffraction. These compounds represent superstructures of the α-ThSi2 structure type through the long- and/or short-range vacancy ordering. RE 4Ge7 (RE = Pr, Nd, Sm) appear to be commensurately modulated 4-fold superstructure of REGe2–x (x = 1/4), while coexistence of commensurate and incommensurate modulation is revealed in the La- and Ce-analogues. These results shed more light on the structural evolution of the REGe2–x phases as function of the vacancy concentration and nature of the rare-earth metal. Measurements of the magnetic susceptibilities on well-characterized single-crystals show ferromagnetic, antiferromagnetic, and even spin-glass-like behaviors. Mean-field theory is used to evaluate the correlations between structural and magnetic property data. Measurements on the electrical resistivities and the heat capacities are also presented and discussed.
ISSN:0020-1669
1520-510X
DOI:10.1021/ic3021645