1/T1 nuclear relaxation time of κ-(BEDT–TTF)2Cu[N(CN)2]Cl : effects of magnetic frustration

We study the role played by the magnetic frustration in the antiferromagnetic phase of the organic salt κ-(BEDT–TTF)2Cu[N(CN)2]Cl. Using the spatially anisotropic triangular Heisenberg model we analyse previous and newly performed NMR experiments. We compute the 1/T1 relaxation time by means of the modified spin wave theory. The strong suppression of the nuclear relaxation time observed experimentally under varying pressure and magnetic field is qualitatively well reproduced by the model. Our results suggest the existence of a close relation between the effects of pressure and magnetic frustration.

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