  The superconductivity and intercalation statein the lithium-and
hexamethylenediamine (HMDA)-intercalated superconductor
Li$_x$(C$_6$H$_{16}$N$_2$)$_y$Fe$_{2-z}$Se$_2$ have been investigated from
powder x-ray diffraction, thermogravimetric and magnetic susceptibility
measurements, changing the intercalation temperature, $T_i$, and the Li
content, $x$. Both Li and HMDA have been co-intercalated stably up to $x$ = 2
roughly in the molar ratio of $x : y = 2 : 1$. In the case of $T_i$ =
45$^\circ$C, it has been found that both Li and HMDA are co-intercalated
locally at the edge of FeSe crystals, indicating that both Li and HMDA are hard
to diffuse into the inside of FeSe crystals at 45$^\circ$C. In the case of
$T_i$ = 100$^\circ$C, on the other hand, it has been found that both Li and
HMDA diffuse into the inside of FeSe crystals, so that $T_c$ tends to increase
with increasing $x$ from ~30 K at $x$ = 1 up to 38 K at $x$ = 2 owing to the
increase of electron carriers doped from Li into the FeSe layers.
