Abstrakt
Single crystals of a new ternary compound Ce3Rh4Sn7 were synthesized by flux method and its crystal structure and magnetic properties were studied by single crystal X-ray diffraction and magnetic suscept-ibility, specific heat and resistivity measurements. Ce3Rh4Sn7 crystallizes in a new monoclinic crystal structure, space group P2(1)/m (No. 11) with Z = 2 and lattice parameters alpha = 9.8708(5) angstrom, b = 4.5779(3) A and c = 14.2381(7) angstrom, beta = 109.535(5)degrees, and V = 606.35(6) A(3).
The structure exhibits three inequivalent Ce-sites. A striking structural motif is the tetragonal pyramid of Rh-ions surrounding the Ce2 yielding an extreme short Ce2-Rh1 spacing of d = 2.7486(10) angstrom.
This strong hint to mixed valent cerium behavior is supported by the entropy analysis. We argue that the Ce2-ion is in a nonmagnetic Ce3+delta state while the other 2 Ce-sites are in a trivalent state.
At low temperatures these latter become partially Kondo screened (TK approximate to 4 K) and order antiferromagnetic below T-N = 2.31 K. The ordering is accompanied by a superzone gap-opening in direction of the magnetic propagation vector Q = (0, 0, l). (c) 2022 Elsevier B.V.
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