Electrical resistance of Ni$_{42+x}$Mn$_{47-x}$Sn$_{11}$ alloys

The electrical resistance and structure of Ni$_{42+x}$Mn$_{47-x}$Sn$_{11}$ alloys have been studied; where $x$ = 0, 1, 2, 3, 4, At room temperature, Ni$_{42+x}$Mn$_{47-x}$Sn$_{11}$ alloys are ordered in the cubic L2$_1$ Ni$_2$MnSn structure characteristic of Heusler alloys. The phase transition between the cubic austenite phase and martensite with lower symmetry, characteristic of ferromagnetic non-stoichiometric Heusler alloys, is observed at temperatures below room temperature. It was found that the partial replacement of Mn atoms by Ni atoms leads to an increase in the phase transition temperatures and to their shift to room temperature.