Effect of Cu Doping on Phase Transition, Thermal Strain, and Thermal Expansion Property in Polycrystalline Ni₅₀Mn_{23−<i>x</i>}Cu_<i>x</i>Ga₂₇ Alloys

The influence of Cu doping on phase transition, thermal strain, and expansion property polycrystalline Ni 50 Mn 23− x Ga 27 ( = 1, 3, 5, 6 7) alloys is investigated. results show that with increasing concentration, martensitic transformation gradually gets close to Curie transition. A magnetostructural transition (MST) observed in samples 7. Such MST can enhance magnitude strain. Besides, possess an isotropic, recoverable, thermally stable Excitedly, effectively tune the properties alloys. Adjustable coefficients from positive negative are obtained by Cu‐doped average linear coefficient α ) between −140.44 −207.70 ppm K −1 7 for a narrow temperature span 11–14 K. When about 72 6) 73 7), which largest Ni–Mn–Ga‐based recently, values decrease −36 . These findings beneficial manipulating Ni–Mn–Ga–Cu their multifunctional applications.