Electrical resistivity of the $\rm Ni_{45}\rm Mn_{46}\rm In_9$ alloy

The structure and electrical resistance of the alloy $\rm Ni_{45}\rm Mn_{46}\rm In_9$ were studied. At room temperature, $\rm Ni_{45}\rm Mn_{46}\rm In_9$ is ordered into the cubic structure $\rm L2_1$, characteristic of Heusler alloys. Throughout the entire temperature range from $77$ to $1100$ K, a large specific resistance and negative temperature coefficient of resistance are observed. Conductivity obeys Mott's law $T^{-1/4}$ with the addition of a metal contribution. The specific features observed in the temperature dependence of the electrical resistance curve suggest that in this alloy the phase transition between the cubic austenitic phase and martensitic phase with lower symmetry, characteristic of ferromagnetic nonstoichiometric Heusler alloys, occurs at an unusually high temperature.