Cu3(tmen)3(tma)2(H2O)2 ·6.5H2O - New S = 1/2 "Sawtooth" Chain?

P. Vrábel a, A. Orendáčováa, J. Černákb and M. Orendáča aCentre of Low Temperature Physics, P.J. Šafárik University & IEP SAS, Park Angelinum 9, SK-04154 Košice, Slovakia bInstitute of Chemistry, P.J. Šafárik University, Moyzesova 11, SK-04154 Košice, Slovakia

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The results of the investigation of magnetic susceptibility, magnetization and specific heat of Cu3(tmen)3(tma)2(H2O)2 ·6.5H2O (tmen = N,N,N',N'-tetra-methylethane-1,2 diamine; H3tma = 1,3,5-benzene-tri-carboxylic acid) are reported. The spatial arrangement of magnetic Cu(II) ions and network of covalent bonds suggest that the studied material might be a representative of S = 1/2 sawtooth chain with moderate exchange coupling J/kB. The investigation of the temperature dependence of susceptibility and magnetic field dependence of magnetization yielding J/kB ≈ - 0.63 K is consistent with the structural features. In addition, specific heat data reveal short-range correlations in milikelvin temperature range and indicate long-range ordering below 150 mK.

DOI: 10.12693/APhysPolA.118.993 PACS numbers: 75.10.Jm, 75.10.Pq, 75.30.Et