CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES |
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Large Barocaloric Effect with High Pressure-Driving Efficiency in a Hexagonal MnNi$_{0.77}$Fe$_{0.23}$Ge Alloy |
Qingqi Zeng1,2, Jianlei Shen1,2, Enke Liu1,3*, Xuekui Xi1, Wenhong Wang1,3, Guangheng Wu1, and Xixiang Zhang4 |
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2University of Chinese Academy of Sciences, Beijing 100049, China 3Songshan Lake Materials Laboratory, Dongguan 523808, China 4Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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Cite this article: |
Qingqi Zeng, Jianlei Shen, Enke Liu et al 2020 Chin. Phys. Lett. 37 076101 |
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Abstract 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 MnNi$_{0.77}$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$\cdot$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 benefits the solid-state cooling.
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Received: 22 April 2020
Published: 21 June 2020
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PACS: |
61.50.Ks
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(Crystallographic aspects of phase transformations; pressure effects)
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63.70.+h
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(Statistical mechanics of lattice vibrations and displacive phase transitions)
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75.30.Sg
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(Magnetocaloric effect, magnetic cooling)
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Fund: Supported by the National Natural Science Foundation of China (Grant No. 51722106), the National Key R&D Program of China (Grant No. 2019YFA0704904), Users with Excellence Program of Hefei Science Center CAS (Grant No. 2019HSC-UE009), and Fujian Institute of Innovation, Chinese Academy of Sciences. |
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