Memory interference in stage-2 CoCl$_{2}$ graphite intercalation

Memory interference effects of aging behavior in stage-2 CoCl$_ {2}$ GIC ($T_{cu}$ = 8.9 K and $T_{cl}$ = 6.9 K)$^{1,2}$ have been studied by low frequency ($f$ = 0.1 Hz) AC magnetic susceptibility and genuine thermoremant magnetization experiments. When the system is aged at multiple stop temperatures ($T_{s}$) for wait times (typically $t_{w} = 3.0 \times 10^{4}$ sec) during a zero-field cooling (ZFC) protocol, the AC magnetic susceptibility exhibits multiple aging holes (dips) at the stop temperatures ($T_{s} < T_{cu}$) on reheating. The depth of the aging hole at $T_{s}$ = 6.0 K is logarithmically proportional to the wait time. The depth of thr aging hole (for the same $t_{w}$) exhibits a local maximum at 6.5 K just below $T_{cl}$. It drastically decreases with increasing temperature and reduces to zero above $T_{cu}$. The genuine thermoremnant magnetization (TRM) measurement also indicates that the memory of the specific spin configurations imprinted at multiple stop temperatures between $T_{cl}$ and $T_ {cu}$ for a wait time during the field-cooled (FC) protocol can be retrieved on reheating. \\ 1. M. Suzuki, I.S. Suzuki, and M. Matsuura, Phys. Rev. B\textbf {73}, 184414 (2006).\\ 2. M. Suzuki, I.S. Suzuki, and M. Matsuura, J. Phys. Condensed Matter in press, Proceeding of HFM 2006, Osaka, Japan (August, 2006).