Thermal Transport in the Quasi-One-Dimensional Spin Chain Compound NiTe2O5

Abstract

One-dimensional magnets are interesting because of the possibility of complex excitation like spinon which is carrying spin-1/2 in the S=1/2 chain[1]. Recently, we have reported a quasi-one-dimensional S=1 chain system NiTe2O5[2]. Regarding the crystallographic structure, NiO6 octahedra are connected to each other through the edge-sharing and spin-1 of Ni2+ ions at the center of the octahedra forms a quasi-one-dimensional spin chain. By decreasing temperature, spin-1 of Ni2+ ions are ordered as antiferromagnetic long-range order at 30.5 K. The single crystal neutron diffraction reveals the unconventional critical behavior of the order parameter around the ordering temperature and a 125Te nuclear magnetic resonance(NMR) experiments reveal the intriguing persistent spin fluctuation above the ordering temperature[3]. Thermal transport have been used to an experimental tool in solid state physics even when dealing with magnetic system[4]. Because heat transport via the spin system itself and thermal conductivities are influenced by scattering between phonon and magnetic excitations. By using the thermal transport experiments on NiTe2O5 single crystal, we studied thermodynamic properties associated with these unusual magnetic behaviors in NiTe2O5.

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