Abstract
The magnetic properties of the organic superconductor beta -(BEDT-TTF)2AuI2 (BEDT-TTF=bis(ethylenedithio)tetrathiofulvalene) have been studied from 300 to 4.2K by ESR spectroscopy and bulk susceptibility measurements using a Faraday balance. The Pauli susceptibility is independent of temperature and has a value of 3.4(3)*10-4 emu mol-1. The temperature dependence of the ESR linewidth is consistent with the behaviour expected for conduction electrons although there is a difference in the angular dependence of the linewidth between 290 and 15K.