Magnetic Properties of a Quantum Ferrimagnet: NiCu(pba)(D_2O)_3 . 2D_2O
Masayuki Hagiwara, Kazuhiko Minami, Yasuo Narumi, Keiji Tatani, Koichi Kindo
Abstract
We report the results of magnetic measurements on a powder sample of NiCu(pba)(D_2O)_3 \cdot 2D_2O
(pba=1,3−propylenebis(oxamato))whichisoneoftheprototypicalexamplesofan
S
=1/2and1ferrimagneticchain.Susceptibility(
\chi
)showsamonotonousincreasewithdecreasingtemperature(T)andreachesamaximumatabout7K.Intheplotof
\chi T
versus
T
,theexperimentaldataexhibitabroadminimumandarefittothe
\chi T
curvecalculatedfortheferrimagneticHeisenbergchaincomposedofS=1/2and1.Fromthisfit,wehaveevaluatedthenearest−neighborexchangeconstant
J/k_B=121 K
,theg−valuesofNi
^{2+}
andCu
^{2+}
,
g_{Ni}
=2.22and
g_{Cu}
=2.09,respectively.Appliedexternalfielddependenceof
\chi T$ at low temperatures is reproduced fairly well by the calculation for the same ferrimagnetic model.