Effect of Sn and Sb element on the magnetism and functional properties of Ni–Mn–Al ferromagnetic shape memory alloys

• Sn and Sb system has same Mn and Ni content and lattice parameter.
• Both systems has disparity in magnetism, entropy change and magnetoresistance.
• Difference was due to change in the Ni 3d–Mn 3d hybridization.
• Sb based alloys are more suitable for mechanical devices.
• Sn based alloys are more suitable for magnetocaloric effect and magnetoresistance.

We have replaced Al partially with Sb and Sn in Ni–Mn–Al systems and investigated its effect on magnetism, entropy change and magnetoresistance in the vicinity of martensitic transformation. Both the samples had identical lattice parameters and Mn contents, which are mostly responsible for magnetism in these systems, yet there were marked changes in magnetic and functional properties of these systems. It was found that the magnetization increased in Sb alloy, while entropy change and magnetoresistance decreased as compared to Sn alloy. These changes are attributed to the change in antiferromagnetic interaction as a result of variation in the Ni d–Mn d hybridization arising due to presence of different sp elements.