Thermal Transport Property of Quasi 1D S =1 chain NiTe2O5

Abstract

One-dimensional magnets are very interesting, although it is well-known that there is no long range-order[1]. Because a spin chain in one-dimensional magnets has the possibility of complex excitations like spinons which have spin-1/2 in chains with S=1/2. Lately, we have reported a quasi-one-dimensional S=1 chain system NiTe2O5[2]. About the crystallographic structural feature of NiTe2O5, NiO6 octahedra are connected to each other through the edge-sharing and the spin(S=1) of each Ni2+ ion at the center of the octahedra forms a quasi-one-dimensional spin chain. By decreasing temperature, spins 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. 125Te nuclear magnetic resonance(NMR) experiments exhibit intriguing persistent spin fluctuation above the ordering temperature[3]. More recently, even magnetoelectric(ME) coupling was reported[4]. Thermal transport has been used to probe magnetic systems as an experimental tool in solid-state physics [5]. Because heat transport via the spin system itself and thermal conductivities are influenced by scattering between phonon and magnetic excitations. By using thermal transport, we studied thermodynamic properties associated with these unusual magnetic behaviors in NiTe2O5.

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