Spin Gap in the Single Spin-1/2 Chain Cuprate Sr${}_{1.9}$Ca${}_{0.1}$CuO${}_3$

Abstract

We report ${}^{63}$Cu nuclear magnetic resonance and muon spin rotation measurements on the S=1/2 antiferromagnetic Heisenberg spin chain compound Sr${}_{1.9}$Ca${}_{0.1}$CuO${}_3$. An exponentially decreasing spin-lattice relaxation rate 1/T${}_1$ indicates the opening of a spin gap. This behavior is very similar to what has been observed for the cognate zigzag spin chain compound Sr${}_{0.9}$Ca${}_{0.1}$CuO${}_2$, and confirms that the occurrence of a spin gap upon Ca doping is independent of the interchain exchange coupling $J^{\prime }$. Our results therefore generally prove the appearance of a spin gap in an antiferromagnetic Heisenberg spin chain induced by a local bond disorder of the intrachain exchange coupling $J$. A low temperature upturn of 1/T${}_1$ evidences growing magnetic correlations. However, zero field muon spin rotation measurements down to 1.5 K confirm the absence of magnetic order in this compound which is most likely suppressed by the opening of the spin gap.

arXiv comment5 pages, 4 figures

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Cited by in corpus (9)

• Heat transport of cuprate-based low-dimensional quantum magnets with strong exchange coupling
• Open XXZ chain and boundary modes at zero temperature
• Finite-size effects in the quasi-one-dimensional quantum magnets Sr${}_2$CuO${}_3$, Sr${}_2$Cu${}_{0.99}$M${}_{0.01}$O${}_3$ (M = Ni, Zn), and SrCuO${}_2$
• Crossover of the high-energy spin fluctuations from collective triplons to localized magnetic excitations in doped Sr14-xCaxCu24O41 cuprate ladders
• Impurities in weakly coupled quantum spin chains Sr${}_2$CuO${}_3$ and SrCuO${}_2$
• The effect of different in-chain impurities on the magnetic properties of the spin chain compound SrCuO${}_2$ probed by NMR
• Spin pseudogap in the $S=\frac{1}{2}$ chain material Sr${}_2$CuO${}_3$ with impurities
• The dynamic structure factor in impurity-doped spin chains
• Suppression of the impurity-induced local magnetism by the opening of a spin pseudogap in Ni-doped Sr${}_2$CuO${}_3$