Electronic structure, magnetic properties and martensitic transformation of Ni50Mn36.5Sb13.5-xSix alloys

• Published in: Journal of magnetism and magnetic materials Vol. 537; p. 168200
• Main Authors: Zhang, Guangrui, Hao, Hongbo, Yao, Te, Qiao, Yu, Liang, Yuping, Liu, Heyan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2021; Elsevier BV
• Subjects: A. silicides; Antimony; Austenite; B. electronic structure; Curie temperature; Doping; Electronic structure; First principles; Heusler alloys; Magnetic properties; Magnetic saturation; Magnetism; Magnetization; Manganese; Martensite; martensitic transformation; Martensitic transformations; Mathematical analysis; Nickel; Phase transitions; Silicon; Transformation temperature; A. silicides; magnetic properties; martensitic transformation; B. electronic structure
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2021.168200

•Effect of Si in Ni50Mn36.5Sb13.5-xSix MSMAs was investigated experimentally and theoretically.•Positive relation between martensitic transformation temperature TM and e/a was determined when Si content is low.•Complex relation between ΔEM and Si content was reported.•Variation of TM can be related to the DOS structure of Ni50Mn36.5Sb13.5-xSix. A series of Ni50Mn36.5Sb13.5-xSix (x = 0 - 2.5) Heusler alloys was prepared. Effect of Si-doping on the formation, martensitic transformation and magnetic properties of Ni-Mn-Sb alloys was investigated experimentally and theoretically. The increasing Si content leads to the increase of the Curie temperature TC and decrease of the saturation magnetization Ms at 5K. The martensitic transformation temperature Tm also shows a decreasing tendency with the substitution of Si for Sb. First-principles calculations indicate that the martensite has a lower total energy comparing with the austenite, which supports the phase transition observed experimentally. The energy difference between the martensite and austenite ΔEM suggests that the martensitic transformation temperature TM will decrease with a small amount of Si-doping, but increase when Si content is high. This explains the decrease of TM observed in the experimental samples, for in these samples, the Si content is in the ΔEM-decreasing region. The calculated total spin moment of the martensite shows a decreasing tendency with increasing Si content, which agrees with the variation of saturation magnetization Ms at 5K.