Trivalent‐Intermediate Valent Cerium Ordering in CeRuSn – A Static Intermediate Valent Cerium Compound with a Superstructure of the CeCoAl Type

Abstract

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(3 + 1)-dimensional crystal and antiferromagnetic structures in CeRuSn

“…The disagreement can be explained by small intensities of superstructure and magnetic reflections involved and the Rietveld type refinement of powder data. The average moment from the single crystal work amounts to 0.61 (6) µ B , which is a somewhat smaller value with respect to the magnetic bulk measurements that led to a value 0.69(1) µ B .…”

“…All the data were properly scaled and corrected for detector efficiency and geometrical factors to derive structure factors. Above room temperature we have fit our data using the computer code FULLPROF [15] to the average 2c crystal structure and arrived to very good agreement with literature sources [6,9]. For the nuclear and magnetic data sets collected at low temperatures we have used the computer code Jana2006 [16] mainly developed by one of us (V.P.)…”

“…This leads to splitting of originally single Ce, Ru and Sn crystallographic positions into two inequivalent sites having different surroundings and different nearest neighbor distances. This led to predictions that Ce atoms are in different valence states, namely intermediate-valence Ce (4−δ)+ (at the Ce1 site) and trivalent Ce 3+ (at the Ce2 sites) states [6,8,10]. Powder magnetic susceptibility behavior is compatible with only part of the Ce ions being in the Ce 3+ state [7,9,10].…”

Ferromagnetic Ordering in CeZnSn

“…The recently reported zinc compound CeRhZn [39] contains two cerium sites with almost tetravalent cerium. In the stannide CeRuSn [17,40] one of the cerium sites is trivalent and the second one is intermediate-valent. In CeZnSn described herein, both cerium sites show a stable trivalent ground state.…”

From REZnSn to REZnSnH1:5 (RE = Pr, Nd) – Inducing Ferromagnetism through Hydrogenation

“…Most of the RETSn stannides crystallize with superstructures of the aristotype AlB 2 [2 -4], with the hexagonal ZrNiAl [5 -7] or the cubic MgAgAs (so-called Half-Heusler phase) type [8,9]. Only CeRuSn [10,11] forms its own peculiar structure type which is a consequence of strong covalent Ce-Ru bonding associated with almost tetravalent cerium.…”