  We report the observation of giant magneto-caloric effect (MCE) in
ferromagnetic shape memory alloys (FSMAs) of nominal compositions
Ni$_2$Mn$_{1.36}$Sn$_{0.64-x}$Ga$_{x}$ ($x$ =0.24, 0.28 and 0.32). Irrespective
of the Ga doping, all the samples undergo long range ferromagnetic ordering
below around 330 K. However, the martensitic transition temperature ($T_{MS}$)
of the samples varies strongly with Ga concentration. Clear signature of field
induced transition around $T_{MS}$ is visible for all the samples. The observed
MCE ($\Delta S$ = 13.6 J/kg K for field changing from 0 to 50 kOe) is found to
be highest for $x$ = 0.28 with peak near 249 K, while $x$ = 0.32 shows $\Delta
S$ = 12.8 J/kg K at 274 K. This series of Ga-doped alloys are found to be
interesting materials with high value of $\Delta S$ over a varied range of
temperature
