ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The structure of Cu2(1,4-diazacycloheptane)2Cl4 consists of well-separated zig-zag chains of Cu atoms, suggesting the possibility of significant antiferromagnetic near-neighbor and next-nearest-neighbor interactions. We report on measurements of magnetic susceptibility χ(H,T) and heat capacity Cp(T) that show that this material does not behave as a simple linear antiferromagnetic chain with spin S=1/2. χ(H=0,T) shows a broad peak at 8 K indicative of one-dimensional antiferromagnetic correlations, but below the peak, χ drops dramatically toward zero instead of remaining finite as T→0. For T(very-much-less-than)Tpeak, χ(H) is independent of field below a critical field Hc≈6.6 T, and rises sharply above Hc to a plateau at 8 T. Below Tpeak, Cp(T)∝exp(−Δ/T) with an activation energy Δ=6.8 K. These data indicate the presence of a gap between the ground state and the lowest-lying excited states. This material is thus a candidate for a model quasi-one-dimensional S=1/2 system with a disordered ground state that is significantly affected by competing interactions. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.362315
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