The investigation of magnetic phase transitions and magnetocaloric properties in high-pressure annealed MnNiFeGe alloy

ABSTRACT

The MnNiFeGe alloy is prepared by high-pressure annealing method. It is found that the martensitic transformation temperature after high-pressure annealing of this alloy decreases with the increasing thermal hysteresis. Besides, another magnetic phase transition above the martensitic transformation is observed, which is due to the existence of a large amount of retained austenite induced by high-pressure annealing. As a result, this alloy shows two positive magnetic entropy change peaks, corresponding to the ferromagnetic phase transition of the austenite and the magnetic martensitic transformation, respectively. The magnetic phase transitions, the variable-temperature crystal-structure evolution, and the magnetocaloric properties of this alloy are investigated in detail.

KEYWORDS:

• MnNiGe alloy
• magnetocaloric effect
• high-pressure annealing
• retained austenite

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51801092], the Natural Science Foundation of Shandong Province [grant number ZR2016EMM17], and the Key Science and Technology Program of Henan Province (Grant No. 212102210449).