Magnetic oscillations amplitude of a dirty quasi two-dimensional organic metal

Magnetoresistance of dirty crystals of the organic metal (BEDO)5Ni(CN)4·3C2H4(OH)2 (where BEDO stands for the bis(ethylenedioxy)tetrathiafulvalene molecule) has been measured up to 54 T at liquid helium temperatures. Quantum oscillations are clearly observed in a large field range even though a Dingle temperature as high as about 13 K is deduced from the field dependence of the oscillations amplitude. This value corresponds to scattering time as low as τ D ∼ 0.1 ps, leading to ω c τ D values (where ω c is the cyclotron pulsation) smaller than 1. Possible origins of the observed low scattering time value are discussed.