Linear-chain mixed-spin antiferromagnets ((Formula presented)(Formula presented)(Formula presented)(Formula presented) were investigated by powder inelastic neutron scattering for x=0.25, 0.5, and x=0.75. Long-range magnetic ordering was observed in all samples. The temperature dependence of the Ni-chain spin-gap modes was measured and compared to previous results for the x=0 and x=1 materials. In the magnetically disordered phase the spin dynamics was shown to have a composition-independent character. The results suggest that one-dimensional gap excitations seen in the paramagnetic and Néel phases of (Formula presented)(Formula presented) are inherently related to Haldane spin excitations in the quantum-disordered system (Formula presented)(Formula presented).
|Number of pages||5|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics