NMR and magnetization measurements in ${\mathrm{Li}}_{0.5}\mathrm{MnPc}$ $(\mathrm{Pc}\equiv {\mathrm{C}}_{32}{\mathrm{H}}_{16}{\mathrm{N}}_8)$, recently proposed as a strongly correlated metal, are presented. Two different low-frequency dynamics are evidenced. The first one, probed by ${}^1\mathrm{H}$ nuclei, gives rise to a slowly relaxing magnetization at low temperature and is associated with the freezing of $\mathrm{MnPc}$ $S=3∕2$ spins. This dynamics is similar to the one observed in pristine $\beta \text{−}\mathrm{MnPc}$ and originates from Li-depleted chain segments. The second one, evidenced by the ${}^7\mathrm{Li}$ spin-lattice relaxation rate, is associated with the hopping of the electrons along Li-rich chains. The characteristic correlation times for the two dynamics are derived, and the role of the disorder is briefly discussed.

• Received 14 June 2006

DOI:https://doi.org/10.1103/PhysRevB.75.085107