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Skutterudites — Physics and Chemistry of Iron Antimonides of Alkali , Alkaline-Earth , and Rare-Earth Metals
| Content Provider | Semantic Scholar |
|---|---|
| Author | Leithe-Jasper, A. Schnelle, Walter Rosner, Helge Baenitz, Michael Borrmann, Horst Burkhardt, Ulrich Ing Grad Gippius, Andrei A. Mydosh, John A. Rabis, Annegrit Ramlau, Reiner Raychaudhuri, Pratap Sheet, Goutam Sichelschmidt, Jörg Wirth, Steffen Viennois, Romain Steglich, Frank Grin, Yuri |
| Copyright Year | 2007 |
| Abstract | The class of compounds known as “skutterudites” exhibits a wealth of topical behaviors. These materials derive from the mineral Skutterudite (CoAs3) [1]. Binary skutterudites having the general chemical formula TX3 are formed by the members of the 9th group of the periodic table T = (Co, Rh, Ir) with pnicogens X = (P, As, Sb). No binary compounds with iron, ruthenium, and osmium could be synthesized so far under equilibrium conditions, obviously for electronic reasons. In order to stabilize such compounds it is necessary to include electropositive elements as a third component leading to the formula MyT4 X12 (filled skutterudites [2,3]). Compounds with rare-earth, actinide, and alkalineearth metals or thallium as cation M were synthesized. Different degrees of filling y can be realized up to y = 1, however, the limits for y depend strongly on the cation M and the “host” T4 X12 and are not yet well explored. In these filled skutterudites the stabilizing M atoms reside in large voids already present in the T4 X12 framework (Fig. 1). A variety of properties have been observed — mainly for rare-earth filled skutterudites — ranging from metal-insulator transitions to magnetic and quadrupole orderings, conventional and unconventional superconductivity, heavy-fermion/nonFermi-liquid behavior, and fluctuating/intermediate valency. Furthermore, interest in these compounds is fueled by their possible use in thermoelectric applications [4]. Many studies suggest that the physics of filled skutterudites is governed by a subtle interplay of the filler ions and their surrounding transition-metal pnicogen host structure. However, only a few publications were devoted to the physics of the host. In order to gain a better understanding of these processes and thus, to explore novel non rare-earth skutterudites, we have successfully synthesized new alkali-metal iron antimonides with sodium and potassium [5]. These light “filler” atoms with selectrons in their conduction bands are not magnetic and, therefore, are a good choice for the investigation of the d-electron influence on the structural chemistry and the physical properties of filled skutterudites. Surprisingly, these compounds order ferromagnetically at about 85 K. The basic properties have already been reported [6,7,5]. In contrast, the alkaline-earth (Ca, Sr, Ba) compounds [3,7,8] remain paramagnetic down to 2 K. Nonetheless, our electronic structure calculations within the local density approach (LDA) indicate that the ground states of Ca, Ba, Yb, and LaFe4Sb12 should also be ferromagnetic. Obviously, strong spin fluctuations not described within the LDA destroy the ferromagnetism. Recently [11], we could prove that Yb in Yb1–xFe4Sb12 is divalent, and that its properties are not caused by the formation of a heavy-electron state, induced by the Kondo effect, at low temperFilled Skutterudites — Physics and Chemistry of Iron Antimonides of Alkali, Alkaline-Earth, and Rare-Earth Metals |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www2.cpfs.mpg.de/~joerg/Homepage_Dr._Jorg_Sichelschmidt/Research_Work_and_Interests_files/SichelschmidtJ,ScRep95(2006)Skutt.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
