High temperature Ni45Co5Mn25−xFexGa20Cu5 ferromagnetic shape memory alloys

• Published in: Scripta materialia Vol. 134; pp. 119 - 122
• Main Authors: Pérez-Checa, A., Feuchtwanger, J., Musiienko, D., Sozinov, A., Barandiaran, J.M., Ullakko, K., Chernenko, V.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2017
• Subjects: Curie temperature; Magnetic shape memory alloys; Martensitic transformation; Ni45Co5Mn25 − xFexGa20Cu5; Tetragonality ratio; Martensitic transformation; Tetragonality ratio; Ni45Co5Mn25−xFexGa20Cu5; Magnetic shape memory alloys; Curie temperature
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2017.03.002

We anticipated that replacing Mn by Fe in the Ni50−yCoyMn25−xFexGa25−zCuz magnetic shape memory alloys would increase their Curie temperature and spontaneous magnetization. In particular, in the set of alloys Ni45Co5Mn25−xFexGa20Cu5 (x=0, …8), a record-breaking combination of high martensitic transformation temperature (400K) and Curie temperature (458K) has been achieved for Ni45Co5Mn21Fe4Ga20Cu5. This alloy shows a non-modulated tetragonal martensite with the lowest lattice distortion ratio, c/a=1.15, near the reverse martensitic transformation temperature. Because of the high Curie temperature and low c/a ratio, the Ni45Co5Mn25−xFexGa20Cu5 and Ni50−yCoyMn25−xFexGa25−zCuz alloys are promising candidates for high temperature magnetic shape memory applications. [Display omitted]