Pd2MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss

• Published in: Advanced science Vol. 10; no. 23
• Main Authors: Ito, Tatsuya, Xu, Xiao, Miyake, Atsushi, Kinoshita, Yuto, Nagasako, Makoto, Takahashi, Kohki, Omori, Toshihiro, Tokunaga, Masashi, Kainuma, Ryosuke
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 15.08.2023; John Wiley and Sons Inc; Wiley
• Subjects: Aging; Alloys; Crystal structure; Energy consumption; Fourier transforms; Heusler alloys; Investigations; martensitic transformation; martensitic transformation hysteresis; metamagnetic shape memory alloys; Pd2MnGa alloy; Temperature; Transmission electron microscopy
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202207779

Metamagnetic shape memory alloys (MMSMAs) are attractive functional materials owing to their unique properties such as magnetostrain, magnetoresistance, and the magnetocaloric effect caused by magnetic‐field‐induced transitions. However, the energy loss during the martensitic transformation, that is, the dissipation energy, Edis, is sometimes large for these alloys, which limits their applications. In this paper, a new Pd2MnGa Heusler‐type MMSMA with an extremely small Edis and hysteresis is reported. The microstructures, crystal structures, magnetic properties, martensitic transformations, and magnetic‐field‐induced strain of aged Pd2MnGa alloys are investigated. A martensitic transformation from L21 to 10M structures is seen at 127.4 K with a small thermal hysteresis of 1.3 K. The reverse martensitic transformation is induced by applying a magnetic field with a small Edis (= 0.3 J mol−1 only) and a small magnetic‐field hysteresis (= 7 kOe) at 120 K. The low values of Edis and the hysteresis may be attributed to good lattice compatibility in the martensitic transformation. A large magnetic‐field‐induced strain of 0.26% is recorded, indicating the proposed MMSMA's potential as an actuator. The Pd2MnGa alloy with low values of Edis and hysteresis may enable new possibilities for high‐efficiency MMSMAs. Metamagnetic shape memory alloys (MMSMAs) are attracting attention as multifunctional materials, such as magnetic actuators and environment‐friendly magnetorefrigeration materials. However, the large energy loss during the phase transformation hinders their applications. In this study, a novel Pd2MnGa MMSMA with extremely small energy loss, which may lead to high efficiency, has been developed.