抄録
We report the results of magnetic measurements on a powder sample of NiCu(pba)(D2O)3· 2D2O (pba=1, 3-propylenebis(oxamato)) which is one of the prototypical examples of an S=1/2 and 1 ferrimagneticchain. Susceptibility(χ) shows a monotonous increase with decreasing temperature (T) and reaches a maximum at about 7 K. In the plot of χ T versus \it{T}, the experimental data exhibit a broad minimum and are fit to the χ T curve calculated for the ferrimagneticHeisenberg chain composed of S=1/2 and 1. From this fit, we have evaluated the nearest-neighbor exchange constant J/kB=121 K, the g-values of Ni2+ and Cu2+, gNi=2.22 and gCu=2.09, respectively.Applied external field dependence of χ T at low temperatures is reproduced fairly well by the calculation for the same ferrimagnetic model.
