ENHANCEMENT OF THE ELECTRONIC SPECIFIC-HEAT COEFFICIENT IN (CO1-XNIX)2SCSN

Both Co2ScSn and Ni2ScSn crystallize with the cubic L2(1) Heusler structure. The electrical resistivity, magnetization, and Mossbauer studies have shown that Co2ScSn undergoes a magnetic transition at T(c) = 238 K and Ni2ScSn is a paramagnet. When Ni is substituted for Co in (Co1-xNix)2ScSn, T(c) decreases linearly with increasing Ni concentration x and goes to zero in the vicinity of x = 0.40. The electronic specific heat coefficient gamma is enhanced from 13 mJ/mol K2 for Co2ScSn (x = 0.0) to 58 mJ/mol K2 for x = 0.40. Gamma remains nearly constant from x = 0.40 to x = 0.50 as the sample moves away from the magnetic instability, and then decreases to about 5 mJ/mol K2 for Ni2ScSn (x = 1.0). The gamma enhancement will be discussed and compared with that observed in the other d-electron and f-electron systems.