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Substitution effects on spin fluctuations in the spin-Peierls compound CuGeO_3

M. Fischer·P. Lemmens·G. Güntherodt·M. Weiden·W. Richter·C. Geibel·F. Steglich
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Abstract

Using Raman scattering we studied the effect of substitutions on 1D spin fluctuations in CuGeO_3 observed as a spinon continuum in frustration induced exchange scattering. For temperatures below the spin-Peierls transition (T_{SP}=14K) the intensity of this continuum at 120-500 cm^{-1} is exponentially suppressed and transferred into a 3D two-magnon density of states. Besides a spin-Peierls gap-induced mode at 30 cm^{-1} and additional modes at 105 and 370 cm^{-1} are observed. Substitution of Zn on the Cu-site and Si on the Ge-site of CuGeO_3 quenches easily the spin-Peierls state. Consequently a suppression of the spin-Peierls gap observable below T_{SP}=14K as well as a change of the temperature dependence of the spinon continuum are observed. These effects are discussed in the context of a dimensional crossover of this compound below T_{SP} and strong spin-lattice interaction.

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M. Fischer, P. Lemmens, G. Güntherodt, M. Weiden, W. Richter, C. Geibel, F. Steglich. 1996-11-07. Substitution effects on spin fluctuations in the spin-Peierls compound CuGeO_3. https://doi.org/10.1016/s0921-4526(96)00773-9

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