  We report temperature (T) dependence of dc magnetization, electrical
resistivity (rho(T)), and heat-capacity of rare-earth (R) compounds, Gd3RuSn6
and Tb3RuSn6, which are found to crystallize in the Yb3CoSn6-type orthorhombic
structure (space group: Cmcm). The results establish that there is an onset of
antiferromagnetic order near (T_N) 19 and 25 K respectively. In addition, we
find that there is another magnetic transition for both the cases around 14 and
17 K respectively. In the case of the Gd compound, the spin-scattering
contribution to rho is found to increase below 75 K as the material is cooled
towards T_N, thereby resulting in a minimum in the plot of rho(T) unexpected
for Gd based systems. Isothermal magnetization at 1.8 K reveals an upward
curvature around 50 kOe. Isothermal magnetoresistance plots show interesting
anomalies in the magnetically ordered state. There are sign reversals in the
plot of isothermal entropy change versus T in the magnetically ordered state,
indicating subtle changes in the spin reorientation with T. The results reveal
that these compounds exhibit interesting magnetic properties.
