Electrical resistivity in SmCoIn₅ under high pressure

SmCoIn₅ crystallizes in the tetragonal HoCoGa5 type structure. This type of crystal structure have attracted much attention because new heavy-fermion superconductivity with very high superconducting transition temperature T_c=18.5 K was discovered in PuCoGa₅. It is expected that Sm has a similar ground state to Pu compounds. Thus we have measured the electrical resistivity on a single crystal of SmCoIn₅ using a cubic anvil pressure cell at temperature 2-300 K under high pressure from 2 to 8 GPa. The value of T_N that was 11.9 K at ambient pressure in SmCoIn₅ increased to 13.2 K at P=2 GPa,. Above 2 GPa, It decreased monotonously with increasing pressure and was 12.6 K at 8 GPa. It may be thought that the 4f electrons in SmCoIn₅ are more localized than 5f electrons in PuCoGa5.