Magnetic field induced martensitic transition in Fe doped Ni-Mn-Sn-B shape memory ribbons

In this study, effect of the Fe-doping on the microstructural evolution, phase transformation and magnetoresistance properties of the Ni-Mn-Sn-B magnetic shape memory ribbons fabricated by melt-spinning technique were investigated. While the phase transition temperatures from austenite to martensite in the undoped ribbon was very close to room temperature, it was found that they decreased by the Fe-doping, which was attributed to decrease in the e/a value with the Fe-content. A voltage change of 5 mu V at a constant current of 1 mA and at 283 K and in the magnetic range of 0-10 kOe was obtained, which is good value obtained for the Heusler alloys. The resistivity data measured in the martensitic - austenite transition region was overlapped at similar to 90 kOe, which is clear evidence for the magnetic field-induced one way martensitic transition. The ribbons showed an antiferromagnetic behavior at low magnetic field and a ferromagnetic behavior at high magnetic fields. The Fe-doping to the Ni-Mn-Sn system caused a significant increase in the magnitude of the magnetization. The results showed that the melt-spinning technique used in the production of magnetic shape memory strips is very promising for magnetic sensor applications.