Quasi-one-dimensional $S=\frac{1}{2}$ Heisenberg antiferromagnetic chain consisting of the organic radical $p$-Br-V

Quasi-one-dimensional $S = \frac{1}{2}$ Heisenberg antiferromagnetic chain consisting of the organic radical $p$ -Br-V

Kenji Iwase, Hironori Yamaguchi, Toshio Ono, Yuko Hosokoshi, Tokuro Shimokawa, Yohei Kono, Shunichiro Kittaka, Toshiro Sakakibara, Akira Matsuo, and Koichi Kindo

Phys. Rev. B 88, 184431 – Published 27 November 2013

Abstract

We have succeeded in synthesizing single crystals of an organic radical $p$ -Br-V [3-(4-bromophenyl)-1,5-diphenylverdazyl]. The dominant intermolecular interactions forming a one-dimensional spin chain are deduced from the molecular packing in the crystal, and the ab initio molecular orbital calculation also indicates such an exchange network. We analyzed the magnetic susceptibility, magnetization curve, and magnetic specific heat through the quantum Monte Carlo method and successfully explained them as being attributed to an $S = \frac{1}{2}$ Heisenberg antiferromagnetic chain. Furthermore, we have found an unexpected successive phase transition in the specific heats, which indicates the formation of a noncollinear magnetic structure induced by frustration.