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CuSiO_3 : a quasi - one - dimensional S=1/2 antiferromagnetic chain system

M. Baenitz·C. Geibel·M. Dischner·G. Sparn·F. Steglich·H. H. Otto·M. Meibohm·A. A. Gippius
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Abstract

CuSiO_3, isotypic to the spin - Peierls compound CuGeO_3, was discovered recently as a metastable decomposition product of the silicate mineral dioptase, Cu_6Si_6O_{18}\cdot6H_2O. We investigated the physical properties of CuSiO_3 using susceptibility, magnetization and specific heat measurements on powder samples. The magnetic susceptibility χ(T) is reproduced very well above T = 8 K by theoretical calculations for an S=1/2 antiferromagnetic Heisenberg linear chain without frustration (α= 0) and a nearest - neighbor exchange coupling constant of J/k_{B} = 21 K, much weaker than in CuGeO_3. Below 8 K the susceptibility exhibits a substantial drop. This feature is identified as a second - order phase transition at T_{0} = 7.9 K by specific heat measurements. The influence of magnetic fields on T_{0} is weak, and ac - magnetization measurements give strong evidence for a spin - flop - phase at μ_0H_{SF} ~ 3 T. The origin of the magnetic phase transition at T_{0} = 7.9 K is discussed in the context of long - range antiferromagnetic order (AF) versus spin - Peierls(SP)order. Susceptibility and specific heat results support the AF ordered ground state. Additional temperature dependent ^{63,65}Cu nuclear quadrupole resonance experiments have been carried out to probe the Cu^{2+} electronic state and the spin dynamics in CuSiO_3.

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M. Baenitz, C. Geibel, M. Dischner, G. Sparn, F. Steglich, H. H. Otto, M. Meibohm, A. A. Gippius. 2000-05-24. CuSiO_3 : a quasi - one - dimensional S=1/2 antiferromagnetic chain system. https://doi.org/10.1103/physrevb.62.12201

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