Frustration induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of $\delta$-(EDT-TTF-CONMe${}_2$)${}_2$AsF${}_6$

Abstract

The $1/4$-filled organic compound, $\delta$-(EDT-TTF-CONMe${}_2$)${}_2$AsF${}_6$ is a frustrated two-dimensional triangular magnetic system as shown by high-frequency (111.2 and 222.4 GHz) electron spin resonance (ESR) and structural data in the literature. The material gradually orders antiferromagnetically below 40~K but some magnetically disordered domains persist down to 4 K. We propose that in defect free regions frustration prevents true magnetic order down to at least 4 K in spite of the large first- and second-neighbor exchange interactions along chains and between chains, respectively. The antiferromagnetic (AFM) order gradually developing below 40 K nucleates around structural defects that locally cancel frustration. Two antiferromagnetic resonance modes mapped in the principal planes at 4~K are assigned to the very weakly interacting one-dimensional molecular chains in antiferromagnetic regions.

References in corpus (15)

• 17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
• Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet
• Phase diagram of the one-dimensional extended Hubbard model at quarter filling
• Extreme sensitivity of a frustrated quantum magnet: Cs_2CuCl_4
• Functional renormalization group for the anisotropic triangular antiferromagnet
• Modes of magnetic resonance in the spin liquid phase of Cs2CuCl4
• Large-N solutions of the Heisenberg and Hubbard-Heisenberg models on the anisotropic triangular lattice: application to Cs${}_2$CuCl${}_4$ and to the layered organic superconductors $\kappa$-(BEDT-TTF)${}_2$X
• Direct determination of exchange parameters in Cs2CuBr4 and Cs2CuCl4: high-field ESR studies
• Dzyaloshinsky-Moriya interaction in vesignieite: A route to freezing in a quantum kagome antiferromagnet
• Geometrical frustration in the spin liquid beta'-Me3EtSb[Pd(dmit)2]2 and the valence bond solid Me3EtP[Pd(dmit)2]2
• Spin diffusion and magnetic eigenoscillations confined to single molecular layers in the organic conductors kappa-(BEDT-TTF)_2Cu[N(CN)_2X (X=Cl, Br)
• Microwave frequency modulation in continuous-wave far-infrared ESR utilizing a quasioptical reflection bridge
• Inter-layer spin diffusion and electric conductivity in the organic conductors κ-ET2-Cl and κ-ET2-Br
• Spin dynamics in S = 1/2 antiferromagnetic chain compounds delta-(EDT-TTF-CONMe_2)_2X (X=AsF_6, Br): a multi-frequency Electron Spin Resonance study
• Multipurpose High Frequency Electron Spin Resonance Spectrometer for Condensed Matter Research