Spin gap in the single spin-1/2 chain cuprate Sr1.9Ca0.1CuO3

Article

关键词: HEISENBERG ANTIFERROMAGNETIC CHAIN;    CHARGE SEPARATION;    COMPOUND SRCUO2;    NMR RELAXATION;    SR2CUO3;    MAGNETIZATION;    SR14CU24O41;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.89.184410

来源: SCIE

【 摘 要 】

We report Cu-63 nuclear magnetic resonance and muon spin rotation measurements on the S = 1/2 antiferromagnetic Heisenberg spin chain compound Sr1.9Ca0.1CuO3. An exponentially decreasing spin-lattice relaxation rate T-1(-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 Sr0.9Ca0.1CuO2, and it confirms that the occurrence of a spin gap upon Ca doping is independent of the interchain exchange coupling J'. Our results therefore suggest that the appearance of a spin gap in an antiferromagnetic Heisenberg spin chain is induced by a local bond disorder of the intrachain exchange coupling J. A low-temperature upturn of T-1(-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.

【 授权许可】

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