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arXiv · 1710.02522

Relative Cooling Power Enhancement by Tuning Magneto-structural Stability in Ni-Mn-In Heusler Alloys

Jing-Han Chen·Nickolaus M. Bruno·Zhenhua Ning·William A. Shelton·Ibrahim Karaman·Yujin Huang·Jianguo Li·Joseph H. Ross Jr
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Abstract

Off-stoichiometric Ni$_2$MnIn Heusler alloys have drawn recent attention due to their large magnetocaloric entropy change associated with the first-order magneto-structural transition. Here we present crystal structural, calorimetric and magnetic studies of three compositions. Temperature-dependent X-ray diffraction shows clear structural transition from a 6M modulated monoclinic to a L2$_1$ cubic. A significant enhancement of relative cooling power (RCP) was achieved by tuning the magnetic and structural stability through minor compositional changes, with the measured results quantitatively close to the prediction as a function of the ratio between the martensitic transition ($T_m$) temperature and austenite Curie temperature ($T_C$) although the maximal magnetic induced entropy change ($\Delta S_{max}$) reduction is observed in the same time. The results provided an evaluation guideline of RCPs as well as magnetic-induced entropy change in designing practical active materials.

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Jing-Han Chen, Nickolaus M. Bruno, Zhenhua Ning, William A. Shelton, Ibrahim Karaman, Yujin Huang, Jianguo Li, Joseph H. Ross Jr. 2017-10-06. Relative Cooling Power Enhancement by Tuning Magneto-structural Stability in Ni-Mn-In Heusler Alloys. https://doi.org/10.1016/j.jallcom.2018.02.050

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