We report the performance of a Ni-Mn-Ga single crystal with a seven-layered lattice modulation (14M martensite), demonstrating large actuation work output driven by an external magnetic field. A magnetic field-induced strain of 11.2%, a twinning stress of 0.64 MPa, and a magneto-crystalline anisotropy energy of 195 kJ/m3 are measured at room temperature, which exceed the best results reported in Ni-Mn-Ga 14M martensites. The produced magnetically induced work output of about 70 kJ/m3 makes the material attractive for actuator applications. Detailed XRD investigation reveals that the studied 14M martensite is stress-induced. With increasing compression stress, the stress-induced intermartensitic transformation sequence 10M → 14M → NM was demonstrated.
Large magnetic field-induced work output in a NiMnGa seven-layered modulated martensite
E. Pagounis, M. J. Szczerba, R. Chulist, M. Laufenberg; Large magnetic field-induced work output in a NiMnGa seven-layered modulated martensite. Appl. Phys. Lett. 12 October 2015; 107 (15): 152407. https://doi.org/10.1063/1.4933303
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