ZERO AND LOW-FIELD ESR OF THE MAGNETIC TRANSITION IN TDAE-C60

The electron spin resonance (ESR) spectra of tetrakis-dimethylamino-et hylene (TDAE)-C60 have been observed in the radiofrequency region and the resonant field - resonance frequency relation has been studied. At T(c) almost-equal-to 15 K a tremendous increase in intensity and a su dden line broadening occur as well as a shift of the center of the ESR line demonstrating the presence of a magnetic transition. A strong no n-zero absorption is seen below T(c) at zero field supporting the abov e statement. The values of the local field are however much smaller th an expected for the case that all C60- spins would order ferromagnetic ally.