We present a model compound for the S=1/2 ferromagnetic Heisenberg chain composed of the verdazyl-based complex [Zn(hfac)2][4-Cl-o-Py-V-(4-F)2]. Abinitio MO calculations indicate a predominant ferromagnetic interaction forming an S=1/2 ferromagnetic chain. The magnetic susceptibility and specific heat indicate a phase transition to an AF order owing to the finite interchain couplings. We explain the magnetic susceptibility and magnetization curve above the phase transition temperature based on the S=1/2 ferromagnetic Heisenberg chain. The magnetization curve in the ordered phase is described by a conventional AF two-sublattice model. Furthermore, the obtained magnetic specific heat reproduces the almost temperature-independent behavior of the S=1/2 ferromagnetic Heisenberg chain. In the low-temperature region, the magnetic specific heat exhibits T dependence, which is attributed to the energy dispersion in the ferromagnetic chain.
@article{arxiv.1903.06896,
title = {$S$ =1/2 ferromagnetic Heisenberg chain in a verdazyl-based complex},
author = {N. Uemoto and Y. Kono and S. Kittaka and T. Sakakibara and T. Yajima and Y. Iwasaki and S. Miyamoto and Y. Hosokoshi and H. Yamaguchi},
journal= {arXiv preprint arXiv:1903.06896},
year = {2019}
}