Magnetic, thermodynamic and transport properties of novel non-centrosymmetric RCoSi3 (R=Pr, Nd and Sm) compounds

Novel non-centrosymmetric RCoSi3 (R = Pr, Nd and Sm) compounds crystallize in tetragonal BaNiSn3 type structure with space group I4 mm. The bulk magnetic ordering of all the compounds were confirmed from heat capacity data. Magnetization measurements indicate that PrCoSi3 orders ferromagnetically at 5.9 K, while NdCoSi3 and SmCoSi3 order antiferromagnetically at 4 K and 8 K respectively. The magnetic transitions were also manifested by the slope change of temperature dependent resistivity at low temperatures. The energy level schemes created by crystal electric field splitting are determined from Schottky contribution to specific heat. The existence of magnon gap like features at low temperatures are consistent in both heat capacity and resistivity for NdCoSi3 and SmCoSi3. Large magnetoresistance is observed in NdCoSi3 and SmCoSi3. First principles electronic structure calculation based on density functional theory framework have been performed and compared with experimental data.