Coherent spin dynamics has been recently observed in high- (S. Bertaina, S. Gambarelli, A. Tkachuk, I. N. Kurkin, B. Malkin, A. Stepanov, and B. Barbara, Nature Nanotechnology 2, 39, 2007; C. Schlegel, J. van Slageren, M. Manoli, E. K. Brechin, and M. Dressel, Phys. Rev. Lett. 101, 147203, 2008) and low spin molecular systems (S. Bertaina, S. Gambarelli, T. Mitra, B. Tsukerblat, A.T. Muller, and B. Barbara, Nature 453, 203, 2008).

The best result was reported so far by A. Ardavan, O. Rival, J. J. L. Morton, S. J. Blundell, A. M. Tyryshkin, G. A. Timco, and R. E. P. Winpenny [Phys. Rev. Lett. 98, 057201, 2007] on molecular Cr₇Ni rings (Spin 1/2) diluted in solution and de-protonated. A decoherence time of 3 microsec was observed at 1.8K that implies a figure of merit Q=T_2/t_g>100 for these systems.

               Cr₇Ni rings