Spin waves and magnetic ordering in the quasi-one-dimensional (formula presented) antiferromagnet (formula presented)

Abstract

Elastic and inelastic neutron scattering were used to study the ordered phase of the quasi-one-dimensional spin-1/2 antiferromagnet (formula presented) The previously proposed model for the low-temperature magnetic structure was confirmed. Spin-wave dispersion along several reciprocal-space directions was measured and interchain, as well as in-chain exchange constants were determined. A small gap in the spin-wave spectrum was observed and attributed to magnetic anisotropy effects. The results are discussed in comparison with existing theories for weakly coupled quantum spin chain antiferromagnets. © 2001 The American Physical Society.