Inverse magnetocaloric effect related to the magnetostructural phase transition in quaternary Ni-Co-Mn-Al alloy

Abstract

The inverse magnetocaloric effect of Ni-Co-Mn-Al quaternary alloy with the relatively low material cost is achieved firstly in a theoretical study (V. Sokolovskiy et al.: J. Appl. Phys., 2020, vol. 127, p. 163901). To investigate and prove this study, the exact composition of Ni40Co10Mn36Al14 alloy is selected and and explored by the combination of X-ray diffraction, scanning electron microscopy, resistivity, and magnetic studies. The quaternary alloy reveals that the main phase is associated with a martensitic L1(0) phase structure with some austenitic B2 phase in the vicinity of room temperature. The results show that the alloy maintains both Austenite and Martensite phases and has a grand scale change in magnetization of approximately 95 emu g(-1) around the Martensitic phase transition (in the range of 20 K) that exhibits a first-order magnetic transition from ferromagnetic to non-ferromagnetic state. The alloy reveals the inverse magnetic entropy change of about 12 and 8 J kg(-1) K-1 and the relative cooling power of 125 and 76 J kg(-1) under only 15 and 10 kOe, respectively. Likewise, the MR value of 11.5 pct obtains in the external magnetic field source of 10 kOe in the heating direction. The experimental results support the referenced theoretical study and make this material prominent in future magnetocaloric and magnetoresistivity studies.