Controlling magnetostructural transition and magnetocaloric effect in multi-component transition-metal-based materials

Proper coupling between structural and magnetic transitions is critical for the emergence and control of magnetocaloric effects in solids. We examine the influence of minor substitutional doping (replacing Mn by Cr and Al by Sn) and interstitial doping with B on the magnetic, structural, and magnetocaloric properties of recently discovered Mn0.5Fe0.5NiSi0.94Al0.06 alloy exhibiting a giant magnetocaloric effect near room temperature. We demonstrate that magnetocaloric properties of the base compound can be controlled and, in some cases, improved by chemical substitutions. First-principles computations elucidate how small changes in the composition affect properties in this family of compounds and, thus, provide useful guidance for the selection of suitable doping elements for such materials. The magnetic-field-induced entropy change measured for Mn0.5Fe0.5NiSi0.94Al0.06B0.005 is -22J/kgK near room temperature for the applied magnetic field of 2T, and it is among the highest known values for this class of materials.

Automated summary

Proper coupling between structural and magnetic transitions is crucial for controlling and improving the magnetocaloric properties of alloys. Chemical substitutions have been demonstrated to effectively control the magnetocaloric properties of Mn0.5Fe0.5NiSi0.94Al0.06 alloy, with B doping leading to one of the highest magnetic-field-induced entropy changes near room temperature.