Abstract Magnetostriction of a non-modulated martensite was measured for Ni2.27Mn0.73Ga ferromagnetic shape memory alloy in steady magnetic fields μ0H up to 10 T at temperatures below room temperature and in μ0H ≤ 1 T at temperatures above room temperature. Linearity of the longitudinal magnetostriction λ|| observed at high fields μ0H > 6 T implies that the magnetostriction is associated with a 3d electron band. The anisotropic magnetostriction obtained in a magnetic field μ0H = 1 T at T = 4.2 K is ∼16 ppm and decreases down to 3 ppm with the increase in temperature. The volume magnetostriction is positive but very small (∼0.6 ppm) under these conditions. In the region of the magnetostructural phase transition the longitudinal and volume magnetostriction showed a complex sigh-changing behavior which depends on the strength of applied magnetic field. Thermal expansion coefficient α of Ni2.27Mn0.73Ga in the martensitic state was measured to be α ∼13 × 10−6 K−1 which is comparable with the thermal expansion coefficient of a non-stoichiometric Ni2.19Mn0.81Ga single crystal.

中文翻译：

---

在高达 10 T 的磁场中研究铁磁形状记忆合金 Ni 2.27 Mn 0.73 Ga 的磁致伸缩

摘要 在低于室温的温度下在高达 10 T 的稳定磁场 μ0H 和在高于室温的温度下在 μ0H ≤ 1 T 的情况下，对 Ni2.27Mn0.73Ga 铁磁形状记忆合金的非调制马氏体的磁致伸缩进行了测量。纵向磁致伸缩的线性λ|| 在高场 μ0H > 6 T 下观察到的表明磁致伸缩与 3d 电子带相关。在 T = 4.2 K 的磁场 μ0H = 1 T 中获得的各向异性磁致伸缩为 ~16 ppm，并随着温度的升高降低至 3 ppm。在这些条件下，体积磁致伸缩为正但非常小（~0.6 ppm）。在磁结构相变区域，纵向和体积磁致伸缩表现出复杂的叹息变化行为，这取决于外加磁场的强度。马氏体状态的 Ni2.27Mn0.73Ga 的热膨胀系数 α 经测量为 α ∼13 × 10-6 K-1，这与非化学计量的 Ni2.19Mn0.81Ga 单晶的热膨胀系数相当。