Nanomaterials (Oct 2022)

Processing Effects on the Martensitic Transformation and Related Properties in the Ni<sub>55</sub>Fe<sub>18</sub>Nd<sub>2</sub>Ga<sub>25</sub> Ferromagnetic Shape Memory Alloy

  • Mihaela Sofronie,
  • Bogdan Popescu,
  • Monica Enculescu,
  • Mugurel Tolea,
  • Felicia Tolea

DOI
https://doi.org/10.3390/nano12203667
Journal volume & issue
Vol. 12, no. 20
p. 3667

Abstract

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The influence of processing on the martensitic transformation and related magnetic properties of the Ni55Fe18Nd2Ga25 ferromagnetic shape memory alloy, as bulk and ribbons prepared by the melt spinning method and subjected to different thermal treatments, is investigated. Structural, calorimetric, and magnetic characterizations are performed. Thermal treatment at 1173 K induces a decrease in both the Curie and the martensitic transformation temperatures, while a treatment at 673 K produces the structural ordering of the ribbons, hence an increase in TC. A maximum value of the magnetic entropy variation of −5.41 J/kgK was recorded at 310 K for the as quenched ribbons. The evaluation of the magnetoresistive effect shows a remarkable value of −13.5% at 275 K on the bulk sample, which is much higher than in the ribbons.

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