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Herein, the magnetic properties and elastocaloric effects of Cu70Al19 + 0.5xMn11−0.5x (x = 0, 1, 2, 3) alloys are investigated. The resistance versus temperature curves indicate that the phase transition temperature increases as the Mn content decreases. In particular, the Cu70Al20.5Mn9.5 alloy exhibits a phase transition temperature close to room temperature. Therefore, the elastocaloric effects of this alloy are examined under stresses ranging from 200 to 500 MPa. The results show that the adiabatic temperature change of the alloy under a stress of 500 MPa reaches 9.8 K. Furthermore, the magnetization curves at 300 K reveal that the magnetic properties of the alloy significantly improve after undergoing low‐temperature aging treatment. The X‐ray diffraction patterns show that this improvement can be attributed to the transformation of the β1 phase to the ferromagnetic phase β3. Overall, the Cu70Al20.5Mn9.5 alloy demonstrates elastocaloric and magnetic properties comparable to those observed in certain Ni–Mn‐based alloys. [ABSTRACT FROM AUTHOR]

The magnetic properties and the existence of spin reorientation have been systematically investigated in MnNiGa ribbons. The thermomagnetic curve reveals that as-spun and annealed ribbons undergo a two-step magnetic structural transformation and the magnetic properties of the annealed ribbons are improved. The splitting behaviour of zero-field-cooled and filed-cooled (ZFC-FC) curve shows that the ribbon has occurred a spin reorientation transformation. The ZFC and isothermal magnetization curves tested by changing the direction of the magnetic field illustrate the existence of magnetic anisotropy, and the direction of H// is easily magnetized. In the direction of easy magnetization, the value of magnetic entropy is about 1.54 J/kg K. The easy magnetization direction is proved to be in-plane by the decrease of the magnetic domain phase shift. It is clear that the magnetoresistance is negative in all temperature ranges and the nonlinear variation at low fields accounts for the presence of spin reorientation. The variation of Hall resistance curve in a low magnetic field reflects the existence of an abnormal Hall effect. [ABSTRACT FROM AUTHOR]

The effect of hydrostatic pressure on the martensitic transformation and magnetocaloric properties of MnNi0.88GeV0.12 alloy is studied in detail. X‐ray diffraction at room temperature shows that the alloy has a single hexagonal Ni2In‐type structure. The phase transition temperature moves to the low‐temperature region with the increase in hydrostatic pressure. Under the external magnetic field of 15 kOe, the hydrostatic pressure driving rates dTM/dP and dTA/dP are 60.25 and 65.25 K GPa−1, respectively, which indicate that the applied pressure expands the working temperature range of magnetic refrigeration. A magnetic entropy change ΔS of −4.8 J kg−1 K−1 is obtained in the external magnetic field of 15 kOe under ambient pressure. The peak value of |ΔS| is increased to 5.6 J kg−1 K−1 under hydrostatic pressure, which is closely related to the structural change of the alloy. [ABSTRACT FROM AUTHOR]

The elastocaloric effect and magnetic performance of Ni50Mn31.5Ti18Cu0.5 shape memory alloy were studied. The analysis of magnetic transformation shows that the transformation temperature of the alloy is close to room temperature. A large unloading rate can make the alloy showing smaller hysteresis and lower plastic deformation, and improve the superplasticity of the alloy. With the increase in loading stress, the cooling effect of the alloy is better. When the loading stress is 600 MPa, the ΔT of the alloy reaches 9 K. The alloy has good cycle stability during 100 cycles. Hence, the refrigeration performance of Ni50Mn31.5Ti18Cu0.5 alloy can be compared with many Ni-Mn-based alloys, which indicates that it is a promising elastocaloric refrigeration material. [ABSTRACT FROM AUTHOR]