F. Scheibel, W. Liu, L. Pfeuffer, N. Shayanfar, A. Taubel, K. P. Skokov, S. Riegg, Y. Wu, O. Gutfleisch

We investigated the effect of Gd-rich precipitates in multicaloric Ni-Mn-In-Heusler alloys on the martensitic transformation, magnetocaloric effect, and mechanical properties. While the excellent magnetocaloric properties of the Ni-Mn-In matrix were maintained with doping, an increase in mechanical strength by 100% was observed in the Gd-doped samples. Our study shows a direct comparison between a Ni-Mn-In Heusler alloys with and without Gd-rich precipitates keeping the transition temperature and grain size the same. Therefore, we could directly relate the increase in mechanical strength to the precipitates. Comparing doping with grain refinement, a higher mechanical strength can be achieved by grain refinement; however, the best improvement is expected for a combination of grain refinement and doping.

In addition, the study shows also the influence of the precipitates on the first-order magnetostructural transition. The slightly increase of thermal hysteresis by doping can be used for designing the transition for multi-caloric cooling, where thermal hysteresis is utilized by using two external stimuli.

J. Appl. Phys. 133, 075104 (2023).
DOI: 10.1063/5.0143507