Structural phase transitions in the kagome lattice based materials Cs2-xRbxSnCu3F12 (x = 0, 0.5, 1.0, 1.5)
Abstract
The solid solution Cs2-xRbxSnCu3F12 (x = 0, 0.5, 1.0, 1.5) has been investigated crystallographically between 100 and 300 K using synchrotron X-ray powder diffraction and, in the case of x = 0, neutron powder diffraction. For Cs2SnCu3F12 (x = 0), there is a structural transition from the previously reported room temperature rhombohedral symmetry (R[3 with combining macron]m) to monoclinic (P21/n) symmetry at 170 K. This transformation is repeated for the x = 0.5 composition, but with an increased transition temperature of 250 K. For x = 1.0 the monoclinic phase is found at 300 K, suggesting that the transition temperature is increased even further. For x = 1.5 a different behaviour, more akin to that previously reported forCs2SnCu3F12, is found: a single phase transition between rhombohedral symmetry (R[3 with combining macron]) and triclinic symmetry (P[1 with combining macron]) is found at 280 K. In agreement with previous single crystal studies, Cs2SnCu3F12 powder exhibits strong antiferromagnetic interactions (Θ ~ −268 K) and long-range magnetic order at TN ~ 19.3 K. The finite magnetic moment observed for T < TN might be explained by a Dzyaloshinskii–Moriya interaction, due to the lowering of symmetry from rhombohedral to monoclinic, which was not suggested in the earlier single crystal study.
Citation
Downie , L J , Black , C , Ardashnikova , E I , Tang , C C , Vasiliev , A N , Golovanov , A N , Berdonosov , P S , Dolgikh , V A & Lightfoot , P 2014 , ' Structural phase transitions in the kagome lattice based materials Cs 2-x Rb x SnCu 3 F 12 (x = 0, 0.5, 1.0, 1.5) ' , CrystEngComm , vol. 16 , no. 32 , pp. 7419-7425 . https://doi.org/10.1039/C4CE00788C
Publication
CrystEngComm
Status
Peer reviewed
ISSN
1466-8033Type
Journal article
Description
The collaboration between the University of St Andrews and Moscow State University was funded by a Royal Society International Exchanges grant, in collaboration with the Russian Foundation for Basic Research (12-03-92604). LJD thanks the EPSRC for a PhD studentship via a Doctoral Training grant (EP/P505097/1). ANV acknowledges support of RFBR through grants 13-02-00174, 14-02-92002 and 14-02-92693. This work was supported in part from the Russian Ministry of Education and Science, Increased Competitiveness Program of NUST (No. K2-2014-036).Collections
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