NMR study of the magnetic properties of the polymerized phase of Cs1C60

We present NMR measurements on the orthorhombic (o)-phase of CS1C60 The C-13 NMR spectrum allows, when the Magic Angle Spinning (MAS) technique is used, to get information about the electronic structure of this phase, which points out that the spin density is not uniformly distributed on the C-60 ball. An estimation of the strength of the quadrupolar effects on Cs-133 is then given, which shows that it is possible to analyse the Cs-133 spin-lattice relaxation time T-1 in terms of magnetic effects. A comparison with the T-1 of C-13 is then justified and allows us to point out the importance of low dimensional antiferromagnetic fluctuations in this compound. We also investigate the nature of the magnetic ground state in Cs1C60: the broadening of the spectra states unambiguously its magnetic nature and a detailed analysis of their shape gives further indications on the antiferromagnetic nature of the magnetic order, which seems characterized by a large amount of disorder.