School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
Phys Chem Chem Phys. 2018 Jul 11;20(27):18484-18490. doi: 10.1039/c8cp02720j.
With the development of magnetic refrigerant technology, magnetic substances with a large magnetocaloric effect (MCE) and nearly zero thermal hysteresis are desired. Although Ni-Mn based Heusler alloys have been found to produce large MCEs and have attracted increasing attention recently, the occurrence of thermal hysteresis accompanying MCE due to the nature of first-order phase transition limits its applications with magnetic refrigeration. Up to now, an effective theory or method to eliminate this thermal hysteresis is still lacking. Here, we propose to utilize the feature of magnetic transition at the morphotropic phase boundary (MPB) to eliminate thermal hysteresis and thus design a MPB-involved phase diagram in Heusler alloys of Ni50Mn36Sb14-xInx (x = 0-14). As theoretically expected, the magnetic transition at MPB really yields a MCE with a negligible thermal hysteresis (∼0 K) and the refrigerant capacity arrives at a maximum value of 108.2 J kg-1 at the composition of x = 9. Our findings provide an effective way to design large MCE materials with zero thermal hysteresis.
随着磁制冷技术的发展，人们希望获得具有大磁热效应（MCE）和近零热滞后的磁性物质。虽然基于 Ni-Mn 的 Heusler 合金已被发现具有较大的 MCE，并引起了越来越多的关注，但由于一阶相变的性质，MCE 伴随着热滞后的发生限制了其在磁制冷中的应用。到目前为止，消除这种热滞后的有效理论或方法仍然缺乏。在这里，我们提出利用在同型相变边界（MPB）处的磁转变特性来消除热滞后，并由此设计了 Ni50Mn36Sb14-xInx（x = 0-14）Heusler 合金中的 MPB 相关相图。正如理论所预期的那样，MPB 处的磁转变确实产生了具有可忽略的热滞后（约 0 K）的 MCE，制冷容量在 x = 9 时达到 108.2 J kg-1 的最大值。我们的发现为设计具有零热滞后的大 MCE 材料提供了一种有效的方法。
