Internal stress dependent structural transition in ferromagnetic Ni–Mn–Ga nanoparticles prepared by ball milling

Peruman, K. Vallal; Mahendran, M.; Seenithurai, S.; Chokkalingam, Ramesh Babu; Singh, Ranjan K.; Chandrasekaran, V.

doi:10.1016/j.jpcs.2010.07.022

Cited by 25 publications

(13 citation statements)

References 35 publications

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“…A straightforward way of preparing Heusler nanoparticles is ball milling of polycrystalline starting materials. − This process, however, is rather crude as it involves high-energy input on debris of the milled material, which may lead to structural changes. Further, Heusler particles which are prepared this way are prone to oxidation and in this sense require very careful handling.…”

mentioning

confidence: 99%

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Gellesch

Dimitrakopoulou

Scholz

et al. 2013

Crystal Growth & Design

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A facile synthesis approach for the synthesis of ternary intermetallic nanocrystals was demonstrated exemplarily with the Heusler compound Co2FeGa. The method, involving prefabricated multiwalled carbon nanotubes which act as a template and protective shell, results in the formation of mainly spherical, chemically stable, and crystalline nanoparticles with a well-defined diameter distribution. As an example, for novel functionalities arising from downscaling a bulk material, we observe an enhancement of the coercive field of the Co2FeGa nanocrystals by a factor of ≈30. Our work can facilitate the exploration and eventually the tuning of physical properties of ternary and other intermetallic compounds at the nanoscale.

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mentioning

confidence: 99%

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Gellesch

Dimitrakopoulou

Scholz

et al. 2013

Crystal Growth & Design

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“…The average strain (ε) in the ball milled samples was calculated using the relation used in Ref. [4,27]. The particle size is 72 nm and it is comparable with transmission electron microscopy measurement.…”

Section: Methodsmentioning

confidence: 66%

“…We find that the internal strain is around 0.8% in the as milled sample that reduces to 0.17% after annealing at 973 K. Moreover diffraction peaks in Figure 1 indicates the presence of residual stress. Indeed residual stress induced tetragonal phase without any modulation has been observed earlier for Ni 2 MnGa [14,[21][22][23][24][25][26][27][28][29][30][31][32][33][34].…”

Section: Methodsmentioning

confidence: 70%

Intermartensitic Transformation in Ni54.8Mn23.2Ga21.7 Ferromagnetic Shape Memory Alloy Nano Powder

Nirmala¹,

K²,

Amuthan³

et al. 2012

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The Ni-Mn-Ga Ferromagnetic shape memory alloys are becoming an important element of sensor and actuator materials due to their large magnetic-field-induced strain and shape memory effect in recent years. The martensitic transformation temperature of the Heusler alloy system has been intensively studied. The Ni 54.8 Mn 23.2 Ga 21.7 irregular agglomerated nanoparticles were prepared by ball milling method, and characterized by x-ray diffraction, differential scanning calorimetry and transmission electron microscopy techniques. These particles reveal a disordered non modulated face centered tetragonal structure. For the first time, nanopowder has been found to undergo a sequence of temperature-induced intermartensitic transformation in addition to the martensitic transformation on cooling. It is believed that relaxation of internal stresses is the main issue in this case. The resistivity of the material has been measured on cooling from 450 K to 300 K. It is observed that the resistivity is maximum in the nano crystalline state and it decreases substantially with decrease of the temperature. Both amorphous and nanocrystalline material coexisted in the ball-milled sample, such a nanomagnetic structure is considered to be ideal for soft nanomagnetic material.

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“…This structure evolution is well in line with previous findings on milled Ni−Mn−Ga alloys, which reported development of a short‐range‐ordered fcc structure, promoted by severe plastic deformation on milling and preceded by the intermediate bct structure. [ 12–16 ] The fcc structure has been reported to coexist in similar milled Ni−Mn−Ga powders with some small amount of the residual Heusler phase. [ 12 ] In addition to structural changes, milling introduces large strains inside the crystallites, which is manifested by peak broadening.…”

Section: Resultsmentioning

confidence: 99%

Suppression and Recovery of Martensitic Transformation and Magnetism in Mechanically and Thermally Treated Magnetic Shape‐Memory Ni−Mn−Ga Melt‐Spun Ribbons

et al. 2021

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As‐melt‐spun Ni50.2Mn28.3Ga21.5 ribbons are subjected to milling and subsequent annealing for various times. With progressing milling time, the martensitic transformation is gradually suppressed, magnetic moment deteriorates, whereas the crystal structure undergoes a body centered tetragonal (bct) into face centered cubic (fcc) change. High‐resolution transmission electron microscopy demonstrates a twin‐deformed zone in fcc powder particles, which works to improve circularity of as‐produced powders. Subsequent annealing of as‐milled powders restores martensitic transformation and magnetism, as well as it reverts the fcc into the original 5M structure. It is hence showcased that due to an allotropic transformation, brittle Heusler alloys are mechanically optimized for 3D printing without loss of their functional properties.

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Internal stress dependent structural transition in ferromagnetic Ni–Mn–Ga nanoparticles prepared by ball milling

Cited by 25 publications

References 35 publications

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Intermartensitic Transformation in Ni54.8Mn23.2Ga21.7 Ferromagnetic Shape Memory Alloy Nano Powder

Suppression and Recovery of Martensitic Transformation and Magnetism in Mechanically and Thermally Treated Magnetic Shape‐Memory Ni−Mn−Ga Melt‐Spun Ribbons

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Internal stress dependent structural transition in ferromagnetic Ni–Mn–Ga nanoparticles prepared by ball milling

Cited by 25 publications

References 35 publications

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co2FeGa

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co2FeGa

Intermartensitic Transformation in Ni54.8Mn23.2Ga21.7 Ferromagnetic Shape Memory Alloy Nano Powder

Suppression and Recovery of Martensitic Transformation and Magnetism in Mechanically and Thermally Treated Magnetic Shape‐Memory Ni−Mn−Ga Melt‐Spun Ribbons

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Product

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Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa