Magnetic, magnetocaloric and magnetotransport properties of RSn _1+xGe_1+xcompounds (R=Gd, Tb, and Er; X=O.1)

We have studied the magnetic, magnetocaloric and magnetotransport properties of RSn_1+xGe_1+x(R=Gd, Tb, and Er; x=0.1) series by means of magnetization, heat capacity and resistivity measurements. It has been found that all the compounds crystallize in the orthorhombic crystal structure described by the centrosymmetric space group Cmcm (No. 63). The magnetic susceptibility and heat capacity data suggest that all the compounds are antiferromagnetic. Large negative values of O in case of GdSn _1.1Ge_0.9 and TbSn_1.1Ge_0.9 indicate that strong antiferromagnetic interactions are involved, which is also reflected in the magnetization isotherms. On the other hand ErSn_1.1Ge _0.9 shows weak antiferromagnetic interaction. The heat capacity data have been analyzed by fitting the temperature dependence and the values of 0_D and y have been estimated. Among these three compounds, ErSn _1.1Ge_0.9 shows considerable magnetic entropy change of 9.5 Jkg K and an adiabatic temperature change of 3.2 K for a field of 50 kOe. The resistivity data in different temperature regimes have been analyzed and the dominant contributions have been identified. All the compounds show small but positive magnetoresistance.