Martensitic transformations and magnetic properties of Ni50−xMn37Sn13Fex(x = 0.5, 1, 1.5) melt-spun ribbons

The present study investigates the influence of iron (Fe) doping on the martensitic transformation and magnetic properties of Ni_50−xMn₃₇Sn₁₃Fe_x(x = 0.5, 1, 1.5) magnetic shape memory alloys in ribbon form. The ribbons were prepared using arc-melting followed by melt-spinning processes and were characterized using X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and vibrating sample magnetometry. Our findings demonstrate that the addition of Fe shifts the martensitic transformation to lower temperatures and increases the Curie point of the austenitic phase, \(T_{c}^{\text A}\), leading to an enhanced magnetism in the austenitic phase. Moreover, a significant increase in the magnetization jump \((\Delta M)\) is observed, from \( 3.3\;{\text{emu\ g}}^{-1} \) for \(x=1\) to \(17 \, {\text{emu\ g}}^{-1} \) for \(x=1.5\) under a \(50 \, \text {Oe}\) applied magnetic field. The structural transformations are also found to be sensitive to the external applied magnetic field. The isothermal magnetization curves exhibit the exchange bias effect, which confirms the coexistence of antiferromagnetic and ferromagnetic coupling in the samples. Furthermore, the exchange bias effect increases with the Fe content.