Effect of Cr addition on the structural, magnetic and mechanical properties of magnetron sputtered Ni–Mn–In ferromagnetic shape memory alloy thin films

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• 作者：Harish Sharma Akkera ; Davinder Kaur
• 刊名：Applied Physics A: Materials Science & Processing
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：122
• 期：12
• 全文大小：2,195 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Condensed Matter
  Optical and Electronic Materials
  Nanotechnology
  Characterization and Evaluation Materials
  Surfaces and Interfaces and Thin Films
  Operating Procedures and Materials Treatment
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0630
• 卷排序：122

文摘

The effect of Cr substitution for In on the structural, martensitic phase transformation and mechanical properties of Ni–Mn–In ferromagnetic shape memory alloy (FSMA) thin films was systematically investigated. X-ray diffraction results revealed that the Ni–Mn–In–Cr thin films possessed purely austenitic cubic L2₁ structure at lower content of Cr, whereas higher Cr content, the Ni–Mn–In–Cr thin films exhibited martensitic structure at room temperature. The temperature-dependent magnetization (M-T) and resistance (R-T) results confirmed that the monotonous increase in martensitic transformation temperatures (T_M) with the addition of Cr content. Further, the room temperature nanoindentation studies revealed the mechanical properties such as hardness (H), elastic modulus (E), plasticity index (H/E) and resistance to plastic deformation (H3/E2) of all the samples. The addition of Cr content significantly enhanced the hardness (28.2 ± 2.4 GPa) and resistance to plastic deformation H3/E2 (0.261) of Ni_50.4Mn_34.96In_13.56Cr_1.08 film as compared with pure Ni–Mn–In film. As a result, the appropriate addition of Cr significantly improved the mechanical properties with a decrease in grain size, which could be further attributed to the grain boundary strengthening mechanism. These findings indicate that the Cr-doped Ni–Mn–In FSMA thin films are potential candidates for microelectromechanical systems applications.