Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8152684 | Journal of Magnetism and Magnetic Materials | 2018 | 8 Pages |
Abstract
Ni45Mn44Sn11 melt spun ribbons have been prepared by melt spinning technique. A single austenite L21 phase with lattice constant 5.945â¯Ã
is confirmed at room temperature. The first order martensite transition is observed from calorimetric, electronic transport and magnetic measurements in our Ni45Mn44Sn11 melt spun ribbon sample. The change in lattice entropy due to martensite transformation is found to be nearly 15â¯Jâ¯kgâ1â¯Kâ1 from calorimetric data, both for heating and cooling cycle. A noticeable shift (â7.5â¯K) of reverse martensite transition for the application of 8â¯T magnetic field has been clearly observed from temperature dependent resistivity measurement. Field induced transformation of martensite phase to austenite phase has also been noticed directly from the field dependent isothermal resistivity data inside martensite transition regime. As a result large negative magnetoresistance of 38% has been observed at 265â¯K. Sharp increase of magnetization, on heating, near reverse martensite transition is also observed due to transformation of weak magnetic martensite phase to ferromagnetic austenite phase. Isothermal magnetization data show magnetic hysteresis near the martensite transition regime due to difference in austenite and martensite phase fraction between increasing and decreasing field. A maximum positive magnetic entropy change of 7.2â¯Jâ¯kgâ1â¯Kâ1 is observed for the field change of 5â¯T. Magnetic hysteresis and refrigerant capacity are the important parameters for magnetic refrigerant material. The maximum value of magnetic hysteresis loss is 16.6â¯Jâ¯kgâ1. However, the net refrigerant capacity is found to be 30.4â¯Jâ¯kgâ1 for Ni45Mn44Sn11 melt spun ribbon sample. The adiabatic temperature change is found to be of â2.68â¯K for application of 5â¯T magnetic field at 276â¯K.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
T. Chabri, A. Venimadhav, T.K. Nath,