ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The material Cu2(1,4-diazacycloheptane)2Cl4 consists of well-separated ladderlike chains of Cu atoms that undergo spontaneous dimerization leading to a singlet ground state. Previous measurements12 have shown that for T≤0.7 K, this singlet ground state exists up to a field HC=6.7. Here we report on heat capacity, Cp(H,T), and neutron scattering studies of this material. For T〈8 K, Cp(H=0,T)∝T−3/2 exp{−Δ/T} with an activation energy Δ=9.8 K. Cp(H,T) shows a finite-T transition for H〉HC, presumably to a canted state. Inelastic neutron scattering on powder samples at H=0 shows a gap of 0.8 meV and a bandwidth for the excitations of 0.6 meV. These excitations exhaust the total moment sum rule, and hence the measured triplet band dominates the magnetic fluctuation spectrum. Comparison of the data with exact diagonalization of finite spin chains shows that the system appears to be close to a spin ladder, but with an additional, weak interrung interaction. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.365179
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