Magnetic properties of the Haldane-gap material [Ni(C2H8N2)2NO2](BF4)


Magnetic properties of the Haldane-gap material [Ni(C2H8N2)2NO2](BF4)

Cizmár, E.; Ozerov, M.; Ignatchik, O.; Papageorgiou, T. P.; Wosnitza, J.; Zvyagin, S. A.; Krzystek, J.; Zhou, Z.; Landee, C. P.; Landry, B. R.; Turnbull, M. M.; Wikaira, J. L.

Abstract. Results of magnetization and high-field electron spin resonance (ESR) studies of the new spin-1 Haldane-chain material [Ni(C2H8N2)2NO2] (BF4) (NENB) are reported. A definite signature of the Haldane state in NENB was obtained. From the analysis of the frequency–field dependence of magnetic excitations in NENB, the spin-Hamiltonian parameters were calculated, yielding ∆/kB = 17.4 K, g = 2.14, D/kB = 7.5K and |E/kB| = 0.7K for the Haldane gap, g factor and the crystal-field anisotropy constants, respectively. The presence of fractional S = 1/2 chain-end states, revealed by ESR and magnetization measurements, is found to be responsible for spin-glass freezing effects. In addition, extra states in the excitation spectrum of NENB have been observed in the vicinity of the Haldane gap; their origin is discussed.

  • Open Access Logo New Journal of Physics 10(2008), 033008

Permalink: https://www.hzdr.de/publications/Publ-11171
Publ.-Id: 11171