Inter-layer spin diffusion and electric conductivity in the organic conductors κ-ET2-Cl and κ-ET2-Br

Abstract

A high frequency (111.2-420 GHz) electron spin resonance study of the inter-layer (perpendicular) spin diffusion as a function of pressure and temperature is presented in the conducting phases of the layered organic compounds, κ-(BEDT-TTF)2-Cu[N(CN)2]X (κ-ET2-X), X=Cl or Br. The resolved ESR lines of adjacent layers at high temperatures and high frequencies allows for the determination of the inter-layer cross spin relaxation time, Tx and the intrinsic spin relaxation time, T2 of single layers. In the bad metal phase spin diffusion is two-dimensional, i.e. spins are not hopping to adjacent layers within T2. Tx is proportional to the perpendicular resistivity at least approximately, as predicted in models where spin and charge excitations are tied together. In κ-ET2-Cl, at zero pressure Tx increases as the bad metal-insulator transition is approached. On the other hand, Tx decreases as the normal metal and superconducting phases are approached with increasing pressure and/or decreasing temperature.

18 pages, 11 figures

References in corpus (9)

• Saturation of electrical resistivity
• Mott transition and transport crossovers in the organic compound $\kappa -(BEDT-TTF{)}_{2}Cu[N(CN{)}_2]Cl$
• Quasi-two-dimensional organic superconductors: a review
• Transport criticality of the first-order Mott transition in a quasi-two-dimensional organic conductor, $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl
• Resistivity studies under hydrostatic pressure on a low-resistance variant of the quasi-2D organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br: quest for intrinsic scattering contributions
• 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
• 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

Cited by in corpus (6)

• Electron spin dynamics of two-dimensional layered materials
• Microscopic coexistence of superconductivity and charge order in organic superconductor ${\beta }^{\prime \prime }$-(BEDT-TTF)${}_4$[(H${}_3$O)Ga(C${}_2$O${}_4$)${}_3$]$\cdot$C${}_6$H${}_5$NO${}_2$
• Two-dimensional magnetism in kappa-(BEDT-TTF)2Cu[N(CN)2]Cl, a spin-1/2 Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interaction
• Interacting electron spins in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]I investigated by ESR spectroscopy
• Dynamics of ethylene groups and hyperfine interactions between donor and anion molecules in $\lambda$-type organic conductors studied by ${}^{69,71}$Ga-NMR spectroscopy
• Frustration induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of $\delta$-(EDT-TTF-CONMe${}_2$)${}_2$AsF${}_6$