  Magnetic properties of $M_{c}$Ta$_{2}$S$_{2}$C ($M$ = Fe, Co, Ni, Cu) have
been studied using SQUID DC and AC magnetic susceptibility. In these systems
magnetic $M^{2+}$ ions are intercalated into van der Waals gaps between
adjacent S layers of host superconductor Ta$_{2}$S$_{2}$C.
Fe$_{0.33}$Ta$_{2}$S$_{2}$C is a quasi 2D $XY$-like antiferromagnet on the
triangular lattice. It undergoes an antiferromagnetic phase transition at
$T_{N}$ (= 117 K). The irreversible effect of magnetization occurs below
$T_{N}$, reflecting the frustrated nature of the system. The AF phase coexists
with two superconducting phases with the transition temperatures $T_{cu} = 8.8$
K and $T_{cl} = 4.6$ K. Co$_{0.33}$Ta$_{2}$S$_{2}$C is a quasi 2D Ising-like
antiferromagnet on the triangular lattice. The antiferromagnetic phase below
$T_{N} = 18.6$ K coexists with a superconducting phase below $T_{cu} = 9.1$ K.
Both Ni$_{0.25}$Ta$_{2}$S$_{2}$C and Cu$_{0.60}$Ta$_{2}$S$_{2}$C are
superconductors with $T_{cu}$ ($= 8.7$ K for Ni and 6.4 K for Cu) and $T_{cl}$
(= 4.6 K common to $M_{c}$Ta$_{2}$S$_{2}$C). Very small effective magnetic
moments suggest that Ni$^{2+}$ and Cu$^{2+}$ spins are partially delocalized.

Superconductivity