Martensitic and inter-martensitic transformations in magnetocaloric Ni2.15Mn0.85Ga Heusler alloy

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • A. Madiligama
  • P. Ari-Gur
  • V. Shavrov
  • Y. Ge
  • J. George
  • I. Musabirov
  • V. Koledov

Detail(s)

Original languageEnglish
Journal / PublicationIEEE Transactions on Magnetics
Volume58
Issue number9
Online published6 Aug 2021
Publication statusPublished - Sep 2022
Externally publishedYes

Abstract

The entropy changes of successive martensitic phase transformations in Ni-Mn-Ga Heusler alloys can be utilized to realize enhanced magnetocaloric properties. A detailed study of phase transformations of one such alloy, Ni2.15Mn0.85Ga, (ΔQ = 4900 J/kg at 343 K, under 140 kOe), is reported here. Upon cooling, the paramagnetic cubic (L21) austenitic phase transforms into a ferromagnetic 7M modulated monoclinic martensitic phase. This phase is stable in a narrow temperature range, and upon further cooling, transforms into a non-modulated ferromagnetic tetragonal (L10) phase. The separation between the equilibrium temperatures of the austenitic and tetragonal martensitic phases is only ~50 K. The alloy undergoes reversible temperature-induced martensitic and inter-martensitic phase transformations with thermal hysteresis of about 25 K. The conclusions from the detailed study of the phase transformations lead to new possibilities to enhance the magnetocaloric effect by utilizing the entropy associated with multi-structural transformations.

Research Area(s)

  • Cooling, Diffraction, Gallium, Magnetic hysteresis, Manganese, Metals, Multi-Structural Transformations, Ni-Mn-Ga Heusler Alloys, Nickel, Thermal hysteresis

Citation Format(s)

Martensitic and inter-martensitic transformations in magnetocaloric Ni2.15Mn0.85Ga Heusler alloy. / Madiligama, A.; Ari-Gur, P.; Ren, Y.; Shavrov, V.; Ge, Y.; George, J.; Musabirov, I.; Koledov, V.

In: IEEE Transactions on Magnetics, Vol. 58, No. 9, 09.2022.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review