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arXiv · 1903.06896

$S$ =1/2 ferromagnetic Heisenberg chain in a verdazyl-based complex

N. Uemoto·Y. Kono·S. Kittaka·T. Sakakibara·T. Yajima·Y. Iwasaki·S. Miyamoto·Y. Hosokoshi·H. Yamaguchi
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Abstract

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]$. $Ab$ $initio$ 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 $\sqrt{T}$ dependence, which is attributed to the energy dispersion in the ferromagnetic chain.

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N. Uemoto, Y. Kono, S. Kittaka, T. Sakakibara, T. Yajima, Y. Iwasaki, S. Miyamoto, Y. Hosokoshi, H. Yamaguchi. 2019-03-16. $S$ =1/2 ferromagnetic Heisenberg chain in a verdazyl-based complex. https://doi.org/10.1103/physrevb.99.094418

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