1/F Noise In The Quasi-Two-Dimensional Organic Superconductor Beta ''-(Et)(2)Sf5ch2cf2so3

We performed resistance noise spectroscopy measurements of a bulk single crystal of the quasi-two-dimensional organic superconductor beta ''-(ET)(2)SF5CH2CF2SO3 and found generic 1=f(alpha)-type spectra. The temperature dependence of the nearly 1/f spectra are well described by a generalized random fluctuation model. Our data suggest that the number of fluctuators and/or their coupling to the electrical resistance depends on the temperature. The phenomenological model for the electronic fluctuations explains a pronounced peak structure in the low-frequency noise at around 100 K in terms of the thermally-activated conformational degrees of freedom of the ET molecules' ethylene endgroups.