Pd2 MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss

Tatsuya Ito; Xiao Xu; Atsushi Miyake; Yuto Kinoshita; Makoto Nagasako; Kohki Takahashi; Toshihiro Omori; Masashi Tokunaga; Ryosuke Kainuma

doi:10.1002/advs.202207779

Pd₂ MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss

Adv Sci (Weinh). 2023 Aug;10(23):e2207779. doi: 10.1002/advs.202207779. Epub 2023 Jun 12.

Authors

Tatsuya Ito¹, Xiao Xu^{1

2}, Atsushi Miyake³, Yuto Kinoshita³, Makoto Nagasako⁴, Kohki Takahashi⁴, Toshihiro Omori¹, Masashi Tokunaga³, Ryosuke Kainuma¹

Affiliations

¹ Department of Materials Science, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-02, Sendai, 980-8579, Japan.
² Organization for Advanced Studies, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan.
³ The Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, 277-8581, Japan.
⁴ Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan.

Abstract

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, E_dis , is sometimes large for these alloys, which limits their applications. In this paper, a new Pd₂ MnGa Heusler-type MMSMA with an extremely small E_dis and hysteresis is reported. The microstructures, crystal structures, magnetic properties, martensitic transformations, and magnetic-field-induced strain of aged Pd₂ MnGa 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 E_dis (= 0.3 J mol^-1 only) and a small magnetic-field hysteresis (= 7 kOe) at 120 K. The low values of E_dis 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 Pd₂ MnGa alloy with low values of E_dis and hysteresis may enable new possibilities for high-efficiency MMSMAs.

Keywords: Heusler alloys; Pd2MnGa alloy; martensitic transformation; martensitic transformation hysteresis; metamagnetic shape memory alloys.

Grants and funding

JPMJFR203B/Fusion Oriented REsearch for disruptive Science and Technology