Defect Engineering: Electron-Exchange Integral Manipulation to Generate a Large Magnetocaloric Effect in Ni41Mn43Co6Sn10 Alloys

A promising magnetocaloric effect has been obtained in Ni-(Co)-Mn-X (X = Sn, In, Sb)-based Heusler alloys, but the low isothermal magnetic entropy change Delta S-M restricts the further promotion of such materials. Defect engineering is a useful method to modulate magnetic performance and shows great potential in improving the magnetocaloric effect. In this work, dense Ni vacancies are introduced in Ni41Mn43Co6Sn10 alloys by employing high-energy electron irradiation to adjust the magnetic properties. These vacancies bring about intense lattice distortion to change the distance between adjacent magnetic atoms, leading to a significant enhancement of the average magnetic moment. As a result, the saturation magnetization of ferromagnetic austenite is accordingly improved to generate a high isothermal magnetic entropy change Delta S-M of 20.0 J/(kg K) at a very low magnetic field of similar to 2 T.

Automated summary

In this study, dense Ni vacancies were introduced in Ni-(Co)-Mn-X Heusler alloys to improve their magnetic properties by changing the distance between magnetic atoms and enhancing the magnetic moment, resulting in a significant enhancement of the magnetocaloric effect with a high isothermal magnetic entropy change under a low magnetic field.