Conduction-electron spin resonance of a tetrathiafulvalene–copper bromide complex, (TTF)x CuBry(x≈ 6; y≈ 4)

Abstract

A Dysonian line due to the skin effect in conduction-electron spin resonance has been observed for (TTF)_x CuBr_y(x≈ 6; y≈ 4) crystals at temperatures above ca. 180 K, when the most conductive axis (i.e. the crystal a axis) was perpendicular to the alternating magnetic field H₁ of the standing microwave in the cavity resonator. In contrast, when the a axis was parallel to H₁, an ordinary e.s.r. spectrum was observed. This angular variation is explained on the basis of the low dimensionality of the metal-like charge transport in the crystals. Below ca. 180 K ordinary e.s.r. spectra were observed for all crystal orientations: this is consistent with the electrical conductivity data, which show a metal–insulator transition around this temperature.