Pd₂ MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss.

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.

SUBMITTER: Ito T 

PROVIDER: S-EPMC10427369 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature