Effect of alloying additions and atomic disordering on the physical properties of magnetic Ni$_2$MnGa-based shape memory alloys

The effect of atomic disordering induced by melt quenching or severe plastic deformation via high-pressure torsion on the physical properties (thermal expansion coefficient, electrical resistivity, thermoelectric power, magnetization) of a stoichiometric Ni$_{50}$Mn$_{25}$Ga$_{25}$ alloy and nonstoichiometric Ni$_{50}$Mn$_{28.5}$Ga$_{21.5}$ alloys with 2 at% Cu or Co is studied in the temperature range 2 K $\le T\le$ 900 K and the magnetic field range $H\le$ 7 MA/m.