Microstructure and magnetocaloric effect of melt-spun Ni52Mn26Ga22 ribbon

Abstract

Microstructural features and magnetocaloric properties of Ni52Mn26Ga22 melt-spun ribbons were studied. Results show that there are four types of differently oriented variants of seven-layered modulated (7M) martensite at room temperature, being twin-related one another and clustered in colonies. Due to the coupled magnetic and structural transformations between parent austenite and 7M martensite, the melt-spun ribbons exhibit a significant magnetocaloric effect. At an applied magnetic field of 5 T, an absolute maximum value of the isothermal magnetic entropy change of 11.4 J kg−1 K−1 is achieved with negligible hysteresis losses.

Martensitic transformations and magnetocaloric effect in Sn-doped NiMnIn shape memory alloy

“…Usually, the signals obtained in the DSC depend on the variation of the heat flow while heating or cooling the sample whereas in the M-T curve, depending on the variation in the magnetic exchange interactions across the structural phase transition, the respective changes in the values of the magnetic moment of the martensite and austenite phase take place Thus in Ni 50 Mn 34 Sn 8 In 8 alloy, one can say that, both the magnetic and structural transformation are occurring simultaneously. Similar type scenario has recently been observed in NiMn-Ga system [14,15].…”

Crystallographic Characterization on Polycrystalline Ni-Mn-Ga Alloys with Strong Preferred Orientation

“…The rapid solidification based on melt-spinning technique has been proven to be an effective processing route for the preparation of ribbon shaped ferromagnetic shape memory alloys [40,41,42,43,44,45,46,47,48,49,50]. This method can avoid long time post heat treatment to achieve the composition homogeneity.…”

A switch-like magnetoresistance of ferromagnetic Ni–Mn–Ga ribbon during martensitic transformation

“…This very large MFIS is due primarily to the rearrangement of martensitic variants, but it is  Corresponding author: Qingxue Huang Email address: qxhuang_pd@163.com obtained only in single crystals. On the other hand, in order to decrease the induction of eddy currents and increase the frequency range of the Ni-Mn-Ga ferromagnetic alloys, the materials can be utilized in the form of a thin layer or ribbon [16][17][18].…”

“…Large magnetocrystalline anisotropy (MCA) has been observed in different Ni-Mn-Ga alloys and the MCA is responsible for the magnetic field induced twin variant reorientation[2,17,22,23]. MFIS has been reported to occur in textured polycrystals and with large grain size in training samples and also in fine-grained systems.…”