Large reversible magnetostrain in polycrystalline Ni50Mn33In17−xGax

The structure and strain behavior associated with martensitic transformation for polycrystalline Ni50Mn33In17−xGax (x = 4, 5, 7, 8) have been investigated. All samples show a bcc Heusler structure at room temperature. A large positive transformation strain parallel the solidification direction and negative strain perpendicular to this direction are observed upon martensitic transformation. The same value of reversible magnetostrain in a magnetic field of 70 kOe is found due to the magnetic field-induced reverse martensitic transformation. The largest value of −0.28% and 0.49% along this two directions were observed for x = 4 sample, which is much larger than that in Co-doped NiMnIn polycrystalline. The strain value shows a little decrease with increasing Ga content. Texture and anisotropy effect on the strain are discussed.