On the magnetic and electrical properties of nearly equiatomic ordered FeRh alloys

Results of measurements on a number of ordered FeRh alloys in the range 49.5-52 at % iron and on the ternary alloys Fe₅₀Rh₄₇Pd₃ and Fe_49.5Rh₄₄Ir_6.5 are reported. The magnetization and the electrical resistivity were measured at 4.2 K in semicontinuous magnetic fields up to 370 kOe and the electrical resistivity in zero field from 4.2K to 1300K. The results show that minor deviations from stoichiometry have a drastic influence on the properties. In particular, the high temperature resistivity decreases rather fast as a function of iron concentration at both sides of stoichiometry. This along with a large magnetoresistance suggests that FeRh has the character of a semimetal.