Interacting electron spins in κ−(BEDT-TTF)2Cu[N(CN)2]I investigated by ESR spectroscopy

Lena Nadine Majer, Björn Miksch, Olga Iakutkina, Takuya Kobayashi, Atsushi Kawamoto, Martin Dressel
2020 Physical review B  
We performed angular and temperature-dependent electron-spin-resonance measurements in the quasi-two-dimensional organic conductor κ-(BEDT-TTF)_2Cu[N(CN)_2]I. The interlayer spin-diffusion is much weaker compared to the Cl- and Br-analogues, which are antiferromagnetic insulator and paramagnetic metal, respectively; κ-(BEDT-TTF)_2Cu[N(CN)_2]I behaves insulating when cooled below T = 200 K. A spin gap (Δ≈ 18 K) opens at low temperatures leading to a spin-singlet state. Due to intrinsic disorder
more » ... substantial number of spins (∼ 1 %) remains unpaired. We observe additional signals below T = 4 K with a pronounced anisotropy indicating the presence of local magnetic moments coupled to some fraction of those unpaired spins.
doi:10.1103/physrevb.102.214430 fatcat:bbrikhttezcybiwlp7edb4jnwq