Effect of Mn concentration on the phase transformation in Ni–Mn–Ga single crystal

Peruman, K. Vallal; Mahendran, M.; Seenithurai, S.

doi:10.1016/j.physb.2010.01.037

Cited by 11 publications

(4 citation statements)

References 38 publications

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“…Figure 2 illustrates the archetypal order of transitions detected in magnetic materials using DSC. The austenite phase Curie temperature (from ferromagnetic to paramagnetic) of Ni 44 Co 6 Mn 40 Sn 10 alloy is shown in Figure 2a at ≈390 K. [ 17 ] Figure 2b displays a martensitic transformation (endothermic peak while heating) at ≈312 K and the Curie transition of austenite phase is noted at ≈372 K. [ 18 ] The endothermic peak at ≈293 K showed in Figure 2c is responsible for a reverse martensitic transformation (from martensite to austenite phase) in Ni 49.5 Mn 28.5 Ga 22 alloy. At ≈350 K, a change in slope corresponding to the Curie point of austenite phase is observed and an endothermic peak, observed in the region between 500 and 600 K, is associated with an order–disorder transition.…”

Section: Introductionmentioning

confidence: 99%

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Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques

Reddy

Lakshya

Raj

et al. 2023

Physica Status Solidi (b)

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Various magnetic materials (for example, ferro, ferri, antiferromagnetic) are characterized by their respective transition temperatures (for example, Curie and Néel transitions). Knowledge of these transition temperatures is vital from an application standpoint. Accurate measurements by suitable characterization techniques are needed for identifying these transitions. Several techniques have been used to identify Curie and Néel transition temperatures, with thermal methods being one of the preferred choice. These thermal methods include differential scanning calorimetry (DSC), differential thermal analysis, and thermogravimetric analysis. Although thermal analysis tools have been popularly used for examining magnetic phase transitions, still much confusion exists on their efficacy and might. This review article highlights the strength and limitations of measuring Curie and Néel transitions by thermal techniques; measurements by DSC were the most common choice in previous works. Considering the intrinsic/fundamental nature of these Curie/Néel transitions, such confusion on their measurements (by thermal techniques) and their subsequent analysis (for the order of transition) suggests that a more comprehensive understanding of the events should be an immediate future goal for the research community, at large.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques

Reddy

Lakshya

Raj

et al. 2023

Physica Status Solidi (b)

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“…Martensitic Transformation (MT) temperature is found to be modified by the occurrence of one or more intermartensitic transformations (IMTs) which can be observed during temperature variation or under mechanical stress [6][7][8][9]. MTs are accompanied by anomalies of the magnetic properties of the ferromagnets [10][11], it plays a vital role in physical metallurgy and shape memory phenomenon. Especially, sharp changes of the saturation magnetization and coercivity [12][13] were observed in the vicinity of the phase transition temperature.…”

Section: Introductionmentioning

confidence: 99%

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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“…Up to now the phase transformation and microstructure of martensite in NiMnGa alloy have been studied widely not only in single crystal but also in polycrystalline alloy [4][5][6][7][8][9]. There are two different physical mechanisms that can be responsible for the magnetic field-induced strains, namely, deformation caused by martensitic transformation which is related with the motion of phase boundary, or the re-arrangement of martensite variant through the motion of twin boundary [10].…”

Section: Introductionmentioning

confidence: 99%

Martensitic Transformation and Shape Memory Effect of Ni53.25Mn21.75Ga25 Ferromagnetic Shape Memory Alloy

Wang

Feng

Cai

et al. 2012

AMR

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The martensitic transformation, crystalline structure, microstructure and shape memory effect of the Ni53.25Mn21.75Ga25 (at.%) alloy are investigated by means of Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and the standard metal strain gauge technique. The XRD results showed that the Ni53.25Mn21.75Ga25 alloy is composed of cubic parent phase at room temperature. TEM observation proved that the typical twin martensite is tetragonal structure and tweed-like contrast which is typical image for the parent phase. A large reversible transformation strain, about 0.54%, is obtained in this undeformed polycrystalline alloy due to martensitic transformation and its reverse transformation. This transformation strain is also increased to 0.65% by the external magnetic field. It is believed that the effect of the magnetic field on the preferential orientation of martensitic variants increases the transformation strain.

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Effect of Mn concentration on the phase transformation in Ni–Mn–Ga single crystal

Cited by 11 publications

References 38 publications

Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques

Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques

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

Martensitic Transformation and Shape Memory Effect of Ni<sub>53.25</sub>Mn<sub>21.75</sub>Ga<sub>25</sub> Ferromagnetic Shape Memory Alloy

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