Abstract
We report investigations on the structure and the magnetic properties of (NNi(. From extended x-ray-absorption fine structure and x-ray-diffraction experiments, we show that (NNi( has a chainlike structure of Ni(II) ions coupled via three anions. High-temperature susceptibility is consistent with one-dimensional antiferromagnetism with J/k=-12 K and g=2.25. Below 10 K, a strong decrease of susceptibility and proton relaxation rate is observed, in agreement with the Haldane prediction of a singlet ground state for the S=1, one-dimensional Heisenberg antiferromagnet. From the magnetization-versus-field data at low temperature, the Haldane gap is estimated to 4.5 K, close to the expected value 0.41 ‖J‖ for the S=1, one-dimensional Heisenberg antiferromagnet.
- Received 22 May 1991
DOI:https://doi.org/10.1103/PhysRevB.44.705
©1991 American Physical Society