Effect of electron density on the martensitic transition in Ni–Mn–Sn alloys

The structure and martensitic transition (MT) temperatures of Ni44Mn45Sn10R (R = Al, Ga, In and Sn) alloys were investigated. Valence electron concentration and cell volume are two main factors affecting the MT temperatures in Ni–Mn based Heusler alloys. Our results indicated that the MT temperatures do not vary monotonously with either of the two factors, but increase with the increasing of electron density. Combining the two factors, electron density might be a more appropriate parameter to describe the variations of MT temperatures.

► A systematic substitution of III main group elements (Al, Ga and In) for Sn in the off-stoichiometric Ni44Mn45Sn11 alloys was performed.
► The martensitic transition temperatures don’t vary monotonously with the variation of valence electron concentration and cell volume respectively.
► The martensitic transition temperatures increase with the increasing of electron density.
► Electron density might be a more appropriate factor to describe the variations of martensitic transition temperatures.