On the effect of cobalt doping on thermoelastic martensitic transformations in ferromagnetic Heusler Ni$_{50-x}$Co$_x$Mn$_{29}$Ga$_{21}$ magnetically controlled shape memory alloys

The phase composition, structure, magnetic and thermoelastic martensitic transformations, and physical properties (magnetic susceptibility, magnetization, electric resistivity) in multicomponent magnetic Ni$_{50-x}$Co$_x$Mn$_{29}$Ga$_{21}$ alloys (with a Co content of $x$ = 0, 1, 2, 3, and 10 at%) exhibiting a magnetically controlled shape memory effect are studied. The critical temperatures of the magnetic transitions and thermoelastic martensitic transformations are determined. It is shown that the studied alloys in the austenitic state are substitutional solid solutions based on a quasi-ternary $L2_1$ superstructure (Ni, Co)$_{50}$Mn$_{29}$Ga$_{21}$.