6% magnetic-field-induced strain by twin-boundary motion in ferromagnetic Ni–Mn–Ga

Murray, S.; Marioni, Miguel A.; Allen, Samuel M.; O’Handley, R. C.; Lograsso, Thomas A.

doi:10.1063/1.1306635

Cited by 1,077 publications

(631 citation statements)

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“…While near stoichiometric Ni 2 MnGa shows cubic L2 1 symmetry in the austenitic phase, the structure of martensitic phase depending on temperature and exact composition are referred as (pseudo-)tetragonal or orthorhombic and can exhibit a modulation. The modulation means a shuffle of (110) planes of L2 1 structure in [1][2][3][4][5][6][7][8][9][10] direction with different periodicity [6]. Modulation with a periodicity of ten lattice planes (10M) or even fourteen lattice planes (14M) has been reported for structures with c/a < 1, which exhibits the MFIS of 6% [7,8] or 10%, respectively [9].…”

Section: Introductionmentioning

confidence: 99%

“…The modulation means a shuffle of (110) planes of L2 1 structure in [1][2][3][4][5][6][7][8][9][10] direction with different periodicity [6]. Modulation with a periodicity of ten lattice planes (10M) or even fourteen lattice planes (14M) has been reported for structures with c/a < 1, which exhibits the MFIS of 6% [7,8] or 10%, respectively [9]. The third martensitic phase observed in Ni-Mn-Ga alloys has non-modulated (NM) tetragonal structure with (c/a) NM § 1.17-1.23, which can be described as bodycentered tetragonal unit cell L1 0 [10].…”

Section: Introductionmentioning

confidence: 99%

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Ab initiostudy of Ni₂MnGa under shear deformation

Zelený

Straka

Sozinov

2015

MATEC Web of Conferences

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Abstract. The effect of shear deformation on Ni2MnGa magnetic shape memory alloy has been investigated using ab initio electronic structure calculations. We used the projector-augmented wave method for the calculations of total energies and stresses as functions of applied affine shear deformation. The studied nonmodulated martensite (NM) phase exhibits a tetragonally distorted L21 structure with c/a > 1. A large strain corresponding to simple shears in <100>{001}, <001>{100} and <010>{100} systems was applied to describe a full path between two equivalent NM lattices. We also studied <10-1>{101} shear which is related to twining of NM phase. Twin reorientation in this system is possible, because applied positive shear results in path with significantly smaller energetic barrier than for negative shear and for shears in other studied systems. When the full relaxation of lattice parameters is allowed, the barriers further strongly decrease and the structures along the twinning path can be considered as orthorhombic.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ab initiostudy of Ni₂MnGa under shear deformation

Zelený

Straka

Sozinov

2015

MATEC Web of Conferences

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“…It is now widely accepted that the magnetic field induced strain (MFIS) occurs in 10M and 14M modulated martensite structures of Ni-Mn-Ga single crystals [1][2][3]. The microstructure of modulated martensites has been thoroughly studied by x-ray and electron backscatter diffraction (EBSD) techniques revealing a more complex character of twin boundaries than earlier assumed [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Non-Modulated Martensite Microstructure With Internal Nanotwins In Ni-Mn-Ga Alloys

Szczerba¹

2015

Archives of Metallurgy and Materials

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The self-accommodated non-modulated martensite of Ni-Mn-Ga single crystal was studied by transmission and scanning electron microscopy in the latter case using the electron backscatter diffraction technique. Three kinds of interfaces existing at different length scales were reported. The first, is the wavy and incoherent interface separating martensite variants observed on the micro-level with no-common crystallographic plane between them. The second is within a single martensite plate where the lattice rotates around one of the {110} pole to accommodate the interfacial curvature between martensite plates. Finally, at the nanoscale the third interface exists, a twin boundary separating internal nanotwins with the {112} type habit plane.Keywords: shape memory alloys; martensite; Ni-Mn-Ga single crystals; interface W pracy przeprowadzono obserwacje mikrostruktury monokryształu Ni-Mn-Ga charakteryzujący się nie-modulowaną strukturą martenzytyczną. Badania przeprowadzono z wykorzystaniem techniki transmisyjnej oraz skaningowej mikroskopii elektronowej. W przypadku drugiej metody zastosowano technikę elektronów wstecznie rozproszonych. Trzy rodzaje granic zostały zaobserwowane oraz opisane. Pierwsza granica jest niekoherentna i występuje w skali mikro pomiędzy płytkami martenzytu, które nie posiadają wspólnej płaszczyzny krystalograficznej o niskich indeksach Millera. Kolejna granica występuje wewnątrz pojedynczej płytki martenzytycznej, której towarzyszy rotacja sieci krystalicznej wokół kierunku {110} obszarów przedzielonych tą granicą w celu akomodacji wygięć granicy występującej między płytkami. W skali nanometrycznej można zaobserwować kolejną granicę równoległą do płaszczyzny krystalograficznej {112} (płaszczyzna bliźniacza), która rozdziela płytki nanobliźniaków.

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“…Heusler and half-Heusler compounds, which crystallize in the F m3m and F 43m structures respectively, as shown in Figure 1, are well-known for a wide variety of exotic functional magnetic properties, including half-metallic ferromagnetism, 8,9 magnetic shape memory, [10][11][12] and magnetocaloric behavior. [13][14][15][16] Heuslers, which have the stoichiometry XY 2 Z, are comprised of four interpenetrating fcc sublattices, such that the X and Z atoms form a rock salt lattice and the Y FIG.…”

Section: Introductionmentioning

confidence: 99%

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Levin

Bocarsly

Wyckoff

et al. 2017

Phys. Rev. Materials

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Materials with a large magnetocaloric response are associated with a temperature change upon the application of a magnetic field, and are of interest for applications in magnetic refrigeration and thermomagnetic power generation. The usual metric of this response is the gravimetric isothermal entropy change ∆SM . The use of a simple proxy for the ∆SM that is based on density functional theory (DFT) calculations of the magnetic electronic structure, suggests that half-Heusler MnNiSb should be a better magnetocaloric than the corresponding Heusler compound MnNi2Sb. Guided by this observation, we present a study of MnNi1+xSb (x = 0, 0.25, 0.5, 0.75, 1.0) to evaluate relevant structural and magnetic properties. DFT stability calculations suggest that the addition of Ni takes place at a symmetrically distinct Ni site in the half-Heusler structure, and support the observation using synchrotron X-ray diffraction of a homogeneous solid solution between the half-Heusler and Heusler endmembers. There is a maximum in the saturation magnetization at x = 0.5, and the Curie temperature systematically decreases with increasing x. ∆SM for a maximum magnetic field change of ∆H = 5 T monotonically decreases in magnitude from −2.93 J kg −1 K −1 in the half-Heusler to −1.35 J kg −1 K −1 in the Heusler compound. The concurrent broadening of the magnetic transition results in a maximum in the refrigerant capacity at x = 0.75. The Curie temperature of this system is highly tunable between 350 K and 750 K, making it ideal for low grade waste heat recovery via thermomagnetic power generation. The increase in ∆SM with decreasing x may be extendable to other MnNi2Z Heusler systems that are currently under investigation for use in magnetocaloric refrigeration applications.

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6% magnetic-field-induced strain by twin-boundary motion in ferromagnetic Ni–Mn–Ga

Cited by 1,077 publications

References 12 publications

Ab initiostudy of Ni₂MnGa under shear deformation

Ab initiostudy of Ni₂MnGa under shear deformation

Non-Modulated Martensite Microstructure With Internal Nanotwins In Ni-Mn-Ga Alloys

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

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6% magnetic-field-induced strain by twin-boundary motion in ferromagnetic Ni–Mn–Ga

Cited by 1,077 publications

References 12 publications

Ab initiostudy of Ni2MnGa under shear deformation

Ab initiostudy of Ni2MnGa under shear deformation

Non-Modulated Martensite Microstructure With Internal Nanotwins In Ni-Mn-Ga Alloys

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

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Product

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Ab initiostudy of Ni₂MnGa under shear deformation

Ab initiostudy of Ni₂MnGa under shear deformation