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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

Understanding of magnetic ordering in Gd-rich compounds

aTechnical University Munich, Synthesis and Characterization of Innovative Materials, Department of Chemistry, Lichtenbergstrasse 4, 85748 Garching b. München, Germany
*Correspondence e-mail: tom.nilges@tum.de

Rare-earth transition-metal pnictides (RE-T-Pn) and related compounds are intriguing materials with a wide range of possible applications. Some randomly selected examples are Skutterudites (Evers et al., 1995[Evers, C. B. H., Jeitschko, W., Boonk, L., Braun, D. J., Ebel, T. & Scholz, U. D. (1995). J. Alloys Compd. 224, 184-189.]) or the rare-earth iron arsenide 1111 superconductors (Kamihara et al., 2008[Kamihara, Y., Watanabe, T., Hirano, M. & Hosono, H. (2008). J. Am. Chem. Soc. 130, 3296-3297.]). Another important class of materials with numerous reported candidates are RE6TX2 representatives. In a combined crystal structure/electronic structure study on Gd6FeBi2, reported in Acta Crystallographica Section C (Zhang et al., 2019[Zhang, J., Kang, Y.-M., Shan, G. & Bobev, S. (2019). Acta Cryst. C75, 562-567.]), a magnetic material with a high TC well above room temperature was reported. Based on the selected elemental composition and its Zr6CoAl2-type structure (Kripyakevich et al., 1970[Kripyakevich, P. I., Burnashova, V. V. & Markiv, V. Ya. (1970). Dopov. Akad. Nauk Ukr. RSR Ser. A, 32, 828-831.]) (prototype structure K2UF6; Zachariasen, 1948[Zachariasen, W. H. (1948). J. Am. Chem. Soc. 70, 2147-2151.]), a TC of 350 K was observed. In a clear and precise way, the authors show that structure parameters like the Gd—Gd distance scales linearly with the TC value for many structurally-related Gd compounds. In contrast, the title compound strongly deviates from this trend. After an excellent structure evaluation and the accurate determination of the gadolinium bond lengths, the authors substanti­ated and inter­preted this finding with the aid of quantum chemical calculations (Fig. 1[link]). They identified strong attractive Gd—Fe interactions rather than weak Gd—Bi ones as being responsible for the strong magnetic coupling. The present study clearly illustrates how important a precise structure determination is to inter­pret and understand physical properties. The exceptional high TC in this case is fully understood after combining experimental diffraction and magnetic data with theory. Metallic Gd6FeBi2 has a very small and almost negligible homogeneity range and it can be regarded more as a line compound rather than an alloy. Gd6FeBi2 might be useful for a plethora of applications and the article of Zhang et al. (2019[Zhang, J., Kang, Y.-M., Shan, G. & Bobev, S. (2019). Acta Cryst. C75, 562-567.]) may help to initiate the first efforts in that direction.

References

First citationEvers, C. B. H., Jeitschko, W., Boonk, L., Braun, D. J., Ebel, T. & Scholz, U. D. (1995). J. Alloys Compd. 224, 184–189.  CrossRef ICSD CAS Google Scholar
First citationKamihara, Y., Watanabe, T., Hirano, M. & Hosono, H. (2008). J. Am. Chem. Soc. 130, 3296–3297.  Web of Science CrossRef ICSD PubMed CAS Google Scholar
First citationKripyakevich, P. I., Burnashova, V. V. & Markiv, V. Ya. (1970). Dopov. Akad. Nauk Ukr. RSR Ser. A, 32, 828–831.  CAS Google Scholar
First citationZachariasen, W. H. (1948). J. Am. Chem. Soc. 70, 2147–2151.  CrossRef ICSD CAS Google Scholar
First citationZhang, J., Kang, Y.-M., Shan, G. & Bobev, S. (2019). Acta Cryst. C75, 562–567.  CrossRef ICSD IUCr Journals Google Scholar

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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
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