The hydrostatic pressure is expected to be an effective knob to tune the magnetostructural phase transitions of hexagonal MM’X alloys (M and M’ denote transition metals and X represents main group elements). We perform magnetization measurements under hydrostatic pressure on an MM’X martensitic MnNi2 0.77 Fe 0.23 Ge alloy. The magnetostructural transition temperature can be efficiently tuned to lower temperatures by applying moderate pressures, with a giant shift rate of –151 K/GPa. A temperature span of 30 K is obtained under the pressure, within which a large magnetic entropy change of –23 J⋅kg −1 K −1 in a field change of 5 T is induced by the mechanical energy gain due to the large volume change. Meanwhile, a decoupling of structural and magnetic transitions is observed at low temperatures when the martensitic transition temperature is lower than the Curie temperature. These results show a multi-parameter tunable caloric effect that benef...

中文翻译：

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六角形MnNi 0.77 Fe 0.23 Ge合金的大气压效应和高压驱动效率

静水压力有望成为调节六角形MM'X合金（M和M'表示过渡金属，X表示主族元素）的磁结构相变的有效旋钮。我们在静水压力下对MM'X马氏体MnNi2 0.77 Fe 0.23 Ge合金进行磁化测量。可以通过施加适度的压力以–151 K / GPa的大位移速率将磁结构转变温度有效地调节到较低的温度。在该压力下获得30 K的温度跨度，其中由于大的体积变化而产生的机械能增益引起–5 J的磁场变化中–23J⋅kg-1 K -1的大磁熵变化。与此同时，当马氏体转变温度低于居里温度时，在低温下观察到结构和磁转变的解耦。这些结果表明，多参数可调节热量效应有益于...