The organic magnetic material TDAE-C-60 is investigated by magnetic su
sceptibility, ESR and Raman measurements. We find that, depending on p
reparation technique, the critical temperature (as determined by ESR)
can vary from 16 to 24 K, the latter being the highest T-c reported so
far for this compound or any non-polymeric organic material composed
entirely of first-row elements. The ESR linewidths in the magnetic sta
te - an indication of the magnitude of the internal field - vary betwe
en 15 and 50 Gauss. Rather unexpectedly, Raman spectra of the 16 K mat
erial do not show a clear 6 cm(-1) shift of the C-60 pentagonal pinch
mode frequency relative to pure C-60 corresponding to transfer of one
electron in the ground state. Instead we obtain a sharp line at 1466 c
m(1) which would imply only a partial charge transfer from TDAE to C-6
0 i.e. a resonating molecular charge sharing between C-60 and TDAE mol
ecules. In contrast, the 24 K sample shows a broad set of lines shifte
d to lower frequency implying that the higher T-c materials may be non
-stoichiometric.