Finite-chain effects on the spin excitations in the S = 1 Haldane system NINO with Cu impurities

✍ Scribed by K. Hirota; S.M. Shapiro; K. Katsumata; M. Hagiwara

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 226 KB
• Volume: 213-214
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(95)00095-q

✦ Synopsis

We measured the spin-excitation spectrum for the quasi-one-dimensional S = 1 antiferromagnet [Ni(C3HloN2)2] NO2(C104) (NINO) and NINO with nominally 5 at% Cu 2 + impurities (N1NO : Cu 2 +) by inelastic neutron scattering. We clearly observed a peak corresponding to an energy gap E~ = 1.2 meV ( ~ 14 K) at ~ = 7t, in both single crystals. The Iow-q spectra are also almost completely identical. However, the q dependence of the integrated intensity shows differences between NINO and NINO : Cu 2 +. The correlation length ~/d is estimated to be 6.0 for NINO and 4.4 for NINO : Cu 2+, where d is the spacing between spins in a chain. These results are consistent with the nature of the localized and disordered state of the Haldane system, which is expected to be robust against finite-chain effects.