Influence of hydrogen bonds on magnetic properties of Cu(dmen)(2)M(CN)(4) (M = Ni, Pt) S=1/2 low-dimensional Heisenberg antiferromagnets

摘要

The magneto-structural correlations in materials Cu(dmen)(2)M(CN)(4), where M = Ni or Pt, and dmen is N,N-dimethylethylenediamine, have been investigated. Specific heat, susceptibility, magnetization and ESR studies of both materials suggest the presence of a weak antiferromagnetic (AFM) exchange interaction. Observed lambda-like anomaly at T-max = 0.2 K in the temperature dependence of the specific heat of studied materials might be attributed to the formation of long-range order due to the presence of exchange coupling between the planes. The entropy removed above the transition temperature represents 50% of the total magnetic entropy suggesting low-dimensional character of the system. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.