Composition dependence on the martensitic structures of the Mn-rich NiMnGa alloys

Jiang, Chengbao; Muhammad, Yousaf; Deng, Liang; Wu, Wei; Xu, Huibin

doi:10.1016/j.actamat.2004.02.024

Cited by 183 publications

(113 citation statements)

References 18 publications

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“…On the other hand, for the (Ga,Fe) samples T C increases with increasing doping concentration over the entire studied range, the slope of the increase being larger when the martensitic and the ferromagnetic transition meet each other. This behaviour is ascribed to the coupling between the magnetic and the structural transitions and the significant increase of M s with x [56] and has been previously observed in Ga substituted for Ni and Mn ternary alloys [57][58][59]. Finally, notice that no signatures of either premartensitic or intermartensitic transitions were observed in these families.…”

Section: Ga Substitutionmentioning

confidence: 79%

Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability

Soto-Parra

Moya

Mañosa

et al. 2010

Philosophical Magazine

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Section: Ga Substitutionmentioning

confidence: 79%

Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability

Soto-Parra

Moya

Mañosa

et al. 2010

Philosophical Magazine

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“…This type of structure has been reported in an experiment where a stoichiometric Ni 2 MnGa single crystal was subjected to external tensile or compression loads along the cubic <100> or <110> crystallographic directions respectively, at room temperature [7]. Furthermore, several investigations evidenced the occurrence of temperature-induced 7M-modulated martensite in Mn-rich [22,23] and Ni-rich [10] Ni-Mn-Ga alloys. Such a Ni-Mn-Ga…”

Section: The "7m" Familymentioning

confidence: 94%

Incommensurate and Commensurate Structural Modulation in Martensitic Phases of FSMA

Righi

Albertini

Paoluzi

et al. 2009

MSF

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Abstract. Magnetic and structural properties in multifunctional FSMA (Ferromagnetic Shape Memory Alloys) belonging to Heusler family are frequently related to the occurrence of structural modulation in martensitic phases. The highest MFIS (Magnetic Field Induced Strain) effect has been observed in Ni-Mn-Ga alloys showing martensitic modulated structures. Depending on the composition, pressure and temperature conditions, this periodic structural distortion, consisting of shuffling of atomic layers along specific crystallographic directions, accompanies the martensitic transformation. Over the years, different modulated martensitic structures have been observed and classified depending upon the periodicity of corresponding superstructure (nM with n=3, 5, 6, 7, 12 etc). On the other hand, it has been demonstrated that in most cases such structural modulation is incommensurate and the crystal structure can be solved by applying superspace approach. The crystallographic representation of different modulated structures, obtained by structure refinement on powder diffraction data, suggests a unified description where every different "nM" periodicity can be straightforwardly represented. It will be presented an overview illustrating structural features of several displacive modulated martensitic lattices. For a specific Ni-Mn-Ga composition, the evolution of structural modulation upon temperature change will be illustrated.

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“…In view of that, a linear change of T M with composition is expected due to the monotonic change in the number of valence electrons which has been well reported in various analogous systems [21][22][23] . However, in the present case the variation of T M with e/a was observed to be non-linear.…”

Section: Phase Transformationsmentioning

confidence: 99%

Effect of Fe on the Martensitic Transition, Magnetic and Magnetocaloric Properties in Ni-Mn-In Melt-spun Ribbons

Kumar¹,

Rao²,

Muthu³

et al. 2016

Def. Sc. Jl.

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IntroductIonThe Ni-Mn-Y (Y = Ga, In, Sn, and Sb) based ferromagnetic Heusler alloys display first order martensitic transitions from cubic to tetragonal or orthorhombic structure upon cooling. Associated with the martensitic transition observed in these alloys several important functional properties such as shape memory effect, inverse magnetocaloric effect and magnetoresistance have been reported [1][2][3] . The martensitic and magnetic transitions in these alloys are composition dependent as they are highly sensitive to the valence electron concentration per atom (e/a) and Mn-Mn interatomic distances 4,5 . In the case of Indium (In) containing alloys, a large inverse magnetocaloric effect (IMCE) in polycrystalline state and significant magnetic field induced strain (MFIS) in single crystals have been reported 6,7 . Recently rapid quenching or melt spinning technique was attempted in various systems such as Ni-Fe-Ga, Ni-Mn-Y (Y = In, Al, Sn, and Ga) alloys [8][9][10][11] . The melt spinning technique has the advantage of producing strong textured polycrystalline ribbons. In the case of magnetic refrigeration applications the use of refrigerant materials in the form of thin films or ribbons can optimize the heat transfer between the working body and the heat-exchange fluid. Additional advantage of melt spun ribbons is that the thin ribbons reduces the eddy current losses and can be utilised at high frequencies. In the recent past, offstoichiometric Ni-Mn-In ribbons has gained lot of interest due to their intriguing martensitic phase transitions, microstructure, associated magnetic, magnetocaloric properties [12][13][14][15][16][17] . In the present study, off-stoichiometric Ni 47 Mn 40 In 13 ribbon composition which reported a large magnetic entropy change of 32 J/kg-K at RT was chosen and Mn was partially substituted by Fe 18. The objective of this work is to understand the effect of Fe on the martensitic transitions, magnetic and magnetocaloric properties in Ni-Mn-In ribbons. Hence, Ni 47 Mn 40-x Fe x In 13 (x = 1, 2, 3, and 5) ribbons were prepared through melt spinning route and studied. ExpErImEntal WorKFour Ni-Mn(Fe)-In alloys were prepared by arc-melting pure metals in an argon atmosphere. Subsequently they were induction melted in a quartz tube and ejected with a 1 bar pressure difference onto a copper wheel rotating at a surface velocity of 17 m/s. The process was carried out in argon environment. As-quenched ribbons were 1.5 mm -2 mm wide, 5 mm -18 mm long and 40 µm -45 µm thick. As-spun ribbons were annealed at 850 o C for 30 min in vacuum and quenched to room temperature using Argon gas. The crystal structure of the constituent phases were examined using an X-ray diffractometer (PHILIPS3121, Cu-K α λ = 1.54058 Ǻ). The compositions of the ribbons were determined by energy dispersive x-ray spectroscopy (EDX) and were found to be close to the nominal composition. The phase transitions between the martensite and austenite phases were determined by differential scanning calorimetry (DSC) with a cooling/he...

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Composition dependence on the martensitic structures of the Mn-rich NiMnGa alloys

Cited by 183 publications

References 18 publications

Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability

Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability

Incommensurate and Commensurate Structural Modulation in Martensitic Phases of FSMA

Effect of Fe on the Martensitic Transition, Magnetic and Magnetocaloric Properties in Ni-Mn-In Melt-spun Ribbons

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Composition dependence on the martensitic structures of the Mn-rich NiMnGa alloys

Cited by 183 publications

References 18 publications

Fe and Co selective substitution in Ni2MnGa: Effect of magnetism on relative phase stability

Fe and Co selective substitution in Ni2MnGa: Effect of magnetism on relative phase stability

Incommensurate and Commensurate Structural Modulation in Martensitic Phases of FSMA

Effect of Fe on the Martensitic Transition, Magnetic and Magnetocaloric Properties in Ni-Mn-In Melt-spun Ribbons

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Product

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Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability

Fe and Co selective substitution in Ni₂MnGa: Effect of magnetism on relative phase stability