Enhanced magnetocaloric effect tuning efficiency in Ni-Mn-Sn alloy ribbons

The present work was undertaken to investigate the effect of microstructure on the magnetic entropy change of Ni50Mn37Sn13 ribbon alloys. Unchanged sample composition and cell parameter of austenite allowed us to study strictly the correlation between the average grain size and the total magnetic field induced entropy change (ΔST). We found that a size-dependent martensitic transformation tuning results in a wide temperature range tailoring (>40 K) of the magnetic entropy change with a reasonably small variation on the peak value of the total field induced entropy change. The peak values varied from 6.0 J kg−1 K−1 to 7.7 J kg−1 K−1 for applied fields up to 2 T. Different tuning efficiencies obtained by diverse MCE tailoring approaches are compared to highlight the advantages of the herein proposed mechanism.