Regular ArticleTemperature dependence of twinning and magnetic stresses in Ni46Mn24Ga22Co4Cu4 alloy with giant 12% magnetic field-induced strain

We study magnetic shape memory alloy Ni46Mn24Ga22Co4Cu4 showing up to 12% magnetic field-induced strain (MFIS). The MFIS is mediated by motion of the compound twin boundaries (CTBs) in non-modulated tetragonal crystal lattice. We present temperature dependences of the twinning stress σTW(T), tetragonality ratio, and magnetic anisotropy energy density KU(T), used for magnetic stress σMAG(T) calculations. With temperature increasing, the twinning stress for CTBs decreases with the slope of ‐0.02 MPa/K, twice slower than observed for type I twin boundaries in 10M Ni-Mn-Ga martensite. We found and explained existence of temperature window, within which the giant MFIS is observed.