Empirical mapping of Ni–Mn–Ga properties with composition and valence electron concentration

Jin, Xianglin; Marioni, Miguel A.; Bono, David; Allen, Samuel M.; O’Handley, R. C.; Hsu, T.Y.

doi:10.1063/1.1453943

Cited by 245 publications

(142 citation statements)

References 16 publications

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“…For example, replacing Mn by Co, Ni, or Cu increases T M , but the value of T M for Ni 2 Mn 1−x Fe x Ga decreases with increasing Fe concentration x. Several authors have shown that the number of e/a is closely related to the value of T M for Ni-Mn-based FSMAs: a large e/a value indicates a high T M [31][32][33]. However, a larger e/a corresponds to a lower T M for Ni 2 Mn 1−x Fe x Ga as mentioned above.…”

Section: Purpose Of This Studymentioning

confidence: 99%

“…The elastic constants of a Ni 0.50 Mn 0.284 Ga 0.216 single crystal were studied by using the ultrasonic continuous-wave method [14]. They investigated the C 11 , C 33 , C 66 , and C 44 modes, and found that every mode exhibited abrupt softening around T M . This lattice softening appears to be affected by the abrupt expansion that occurs just above T M when cooling from the austenite phase.…”

Section: Magnetostriction and Magnetic Field-induced Strain Of Ferroamentioning

confidence: 99%

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Magnetostriction of Ni2Mn1−xCrxGa Heusler Alloys

Sakon

Fujimoto

Kanomata

et al. 2017

Metals

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Among the functionalities of magnetic Heusler alloys, magnetostriction is attracting considerable attention. The alloy Ni 2 MnGa has a premartensite phase, which is a precursor state to the martensitic transition. Some researchers have observed magnetostriction in this alloy in the premartensite phase. We performed magnetostriction studies on the premartensite phase of related Cr-substituted Ni 2 Mn 1−x Cr x Ga alloys and measured the thermal strain, permeability, magnetisation, and magnetostriction of polycrystals. Our thermal expansion measurements show an anomaly that indicates the occurrence of lattice deformation below the premartensitic transition temperature T P . Our permeability measurements also showed an anomaly at the premartensitic transition. From our magnetisation results, we obtained the magnetic-anisotropy constant K 1 . In the martensite phase, we found that the magnetic-anisotropy constant of the x = 0.00 alloy is larger than that of the x = 0.15 alloy. At 0.24 MA/m, we obtained a magnetostriction of −120 ppm for the x = 0.15 alloy. Magnetostriction in the premartensite phase is larger than that in the austenite and martensite phases at low magnetic-field strength, thus indicating that it is related to lattice softening in the premartensite phase. The e/a is proportional to the magnetostriction and T P , which indicates that the electron energy, the magnetostriction, and the T p are correlative each other.

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Section: Purpose Of This Studymentioning

confidence: 99%

Section: Magnetostriction and Magnetic Field-induced Strain Of Ferroamentioning

confidence: 99%

Magnetostriction of Ni2Mn1−xCrxGa Heusler Alloys

Sakon

Fujimoto

Kanomata

et al. 2017

Metals

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“…It was established 6,7 that for Ni-Mn-Ga, the phase stability is controlled by the average number of valence electrons per atom. In Fig.…”

mentioning

confidence: 99%

Magnetic properties and martensitic transition in annealed Ni50Mn30Al20

Mañosa¹,

Planes²,

Acet³

et al. 2003

Journal of Applied Physics

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We have studied the effect of heat treatment on the magnetic properties and on the martensitic transition of the Ni 50 Mn 30 Al 20 alloy. A mixed L2 1 ϩB2 state is obtained in the as-prepared sample, while no L2 1 order is retained in the sample quenched from high temperature. For the two heat treatments, the samples order antiferromagnetically, but there is evidence of coexisting ferromagnetic interactions. A martensitic transition occurs below the magnetic one for quenched samples. However, the martensitic transition is inhibited in the as-prepared sample. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1555977͔ Magnetic alloys undergoing structural transitions have received much attention due to the peculiar properties arising from the coupling between structure and magnetism. Among them, magnetic field induced strains 1 and magnetocaloric effect 2 are of particular interest due to their potential application as sensors and actuators and as magnetic refrigerators. This article reports results on Ni-Mn-Al alloys, which are potential candidates to exhibit giant magnetic field induced strains. 3 These magnetic induced strains occur in ferromagnetic systems undergoing a martensitic transformation. They originate from the reorientation of martensite domains promoted by the difference in the Zeeman energy. 4 Currently, the only alloy which has shown giant ͑up to 10%͒ deformations 5 is the Ni-Mn-Ga alloy, for compositions close to the stoichiometric Ni 2 MnGa. However, the brittelness of this alloy has prompted the research of alternative materials.It was established 6,7 that for Ni-Mn-Ga, the phase stability is controlled by the average number of valence electrons per atom. In Fig. 1 we compare the phase diagram of Ni-Mn-Al to that of Ni-Mn-Ga. It is assumed that the number of valence electrons per atom for Ni, Mn, Ga, and Al atoms are 10 (3d 8 4d 2 ), 7 (3d 5 4s 2 ), 3 (4s 2 4p 1 ), and 3 (3s 2 3p 1 ), respectively. The phase diagram of Ni-Mn-Al agrees with the restricted data previously published. 8 From the figure it is clear that for this alloy, the stability of the different phases is controlled by the valence electron concentration as occurs with Ni-Mn-Ga. The phase diagrams of the two alloy systems exhibit a number of general trends. At high temperatures the alloys exhibit a nearest-neighbors ordered structure, B2 ͑Pm3m͒, and upon cooling, next-nearest neighbors order, L2 1 (Fm3m) is expected to develop. For Ni-Mn-Al, the transition line for this order-disorder transition is located at temperatures significantly lower than for Ni-Mn-Ga. This results in a very slow kinetics for the ordering process, and recent studies on a stoichiometric compound 9 have shown that long time annealings just below the order-disorder line do not stabilize a single L2 1 phase, but rather a mixed L2 1 ϩB2 state. This is in contrast to NiMn-Ga alloys for which the B2-L2 1 transition occurs very fast. 10 At temperatures close to room temperature, magnetic ordering occurs. The L2 1 phase is ferromagnetic and for NiMn-Al, the ma...

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“…It is widely accepted that the valance electron concentration, e/a, affects the transformation temperature in Ni-Mn-Ga alloys [23,24]. The number of valence electrons is assumed to be 10 for Ni, 7 for Mn, 3 for Ga and 9 for Co.…”

Section: Phase Transformation Temperaturesmentioning

confidence: 99%

Effect of Co on the martensitic transformation, crystal structure and magnetization of Ni52.5Mn23.5Ga24 based ferromagnetic shape memory alloys

Yan

Chi

et al. 2011

Chin. Sci. Bull.

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Five (Ni 52.5 Mn 23.5 Ga 24 ) 100-x Co x (x = 0, 2, 4, 6, 8) alloys were prepared by arc melting, and the effects of Co addition on the martensitic phase transformation, crystal structure and magnetization were investigated. The phase transformation temperatures M s , M f , A s and A f are proportional to the content of Co in the (Ni 52.5 Mn 23.5 Ga 24 ) 100-x Co x alloys, which appears to be due to the variation in the valance electron concentration. The Curie temperature is sensitive to the composition of the alloy. As the amount of Co changes, both the Co-Mn exchange interaction and the distance between Mn atoms change. These, in turn, affect the Curie temperature and magnetization behavior of the alloy. The martensite phases in all the alloys are domained in three different orientations, the domain boundary was determined to belong to the family of {1 1 2} lattice planes. a magnetic field than thermally controlled shape memory alloys [5,6], which makes them highly interesting for many novel technological applications especially as actuators [7,8]. The induced strain from the magnetic field forces a rearrangement of the crystallographic orientation of the martensitic variants formed during the thermoelastic martensitic transformation [9]. The martensitic transformation start temperature, M s , of a Ni 2 MnGa based alloy is strongly depended on its composition; the Curie temperature (T C ) is, however, less sensitive [10]. The temperature range for producing the magnetic field induced strain, which can be up to 10% of the value, is determined by the M s and T C and can be optimized for specific applications by changes in the alloy composition. Ni-Mn-Ga alloy, Martensitic transformation, domain boundary, Curie temperature, magnetizationOther than the elements Fe [11][12][13] [18] and others, which have been confirmed to affect the characteristics of these Ni-Mn-Ga Heusler alloys, the ferromagnetic 3d transition element Co has been frequently used to modify phase transformation temperatures,

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Empirical mapping of Ni–Mn–Ga properties with composition and valence electron concentration

Cited by 245 publications

References 16 publications

Magnetostriction of Ni2Mn1−xCrxGa Heusler Alloys

Magnetostriction of Ni2Mn1−xCrxGa Heusler Alloys

Magnetic properties and martensitic transition in annealed Ni50Mn30Al20

Effect of Co on the martensitic transformation, crystal structure and magnetization of Ni52.5Mn23.5Ga24 based ferromagnetic shape memory alloys

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