ESR transmission experiments on beta'-(ET)2SF5CF2SO3 and ET2SF5NNO2,investigations of spin-peierls systems

摘要

An anisotropic temperature dependent ESR investigation of the organic systems B'-(ET)2SF5CF2SO3 and (ET)2SFF5NNO2 has led to the indication of a spin-Peierls transition at TSP=33, and 5K, respectively. We present the details of our investigation and place our data in the context of the general spin-Peierls theory. We also show the dc susceptibility SQUID measurements revealing novel behavior in the second material. Note that to access the high field regime, large fields and high frequencies are needed.