High-temperature magnetic anomaly via suppression of antisite disorder through synthesis route modification in a Kitaev candidate Cu2IrO3

Yuya Haraguchi; Daisuke Nishio-Hamane; Akira Matsuo; Koichi Kindo; Hiroko Aruga Katori

doi:10.1088/1361-648X/ad5d3a

High-temperature magnetic anomaly via suppression of antisite disorder through synthesis route modification in a Kitaev candidate Cu₂IrO₃

J Phys Condens Matter. 2024 Jul 8;36(40). doi: 10.1088/1361-648X/ad5d3a.

Authors

Yuya Haraguchi¹, Daisuke Nishio-Hamane², Akira Matsuo², Koichi Kindo², Hiroko Aruga Katori¹

Affiliations

¹ Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
² The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.

PMID: 38941989
DOI: 10.1088/1361-648X/ad5d3a

Abstract

By incorporating inert KCl into the Na₂IrO₃+ 2CuCl → Cu₂IrO₃+ 2NaCl topochemical reaction, we significantly reduced the synthesis temperature of Cu₂IrO₃from the 350 °C reported in previous studies to 170 °C. This adjustment decreased the Cu/Ir antisite disorder concentration in Cu₂IrO₃from ∼19% to ∼5%. Furthermore, magnetic susceptibility measurements of the present Cu₂IrO₃sample revealed a weak ferromagnetic-like anomaly with hysteresis at a magnetic transition temperature of ∼70 K. Our research indicates that the spin-disordered ground state reported in chemically disordered Cu₂IrO₃is an extrinsic phenomenon, rather than an intrinsic one, underscoring the pivotal role of synthetic chemistry in understanding the application of Kitaev model to realistic materials.

Keywords: Kitaev model; honeycomb lattice; quantum spin liquid; spin–orbit coupling.