Reduced size of ordered moments of a quasi 1d antiferromagnet Sr{sub 2}CuO{sub 3}

The quasi one-dimensional antiferromagnet Sr{sub 2}CuO{sub 3} exhibits Neel order of Cu{sup 2+} moments (S = 1/2) at T{sub N} = 5.41(1) K, as demonstrated by (1) almost resolution-limited magnetic Bragg reflections in neutron scattering measurements, and (2) spontaneous muon spin precession in zero-field muon spin relaxation ({mu}SR) measurements. The temperature dependence of the order parameters are consistent between the two experimental techniques. From the neutron data, the authors obtained an upper-limit for the ordered moment size of {approximately} 0.06 {mu}{sub B}. This indicates a significant moment reduction from quantum fluctuations.