Structural and magnetic phase transitions in shape-memory alloys<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mn</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mi mathvaria

Васильев, А. Н.; Bozhko, A. D.; Ховайло, В. В.; Dikshteǐn, I. E.; Шавров, В. Г.; Buchelnikov, V. D.; Matsumoto, M.; Suzuki, Shigeru; Takagi, Toshiyuki; Tani, Junji

doi:10.1103/physrevb.59.1113

Cited by 424 publications

(241 citation statements)

References 17 publications

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“…It is clear that a decrease of about 46 K is driven by an external magnetic field of 5 T. The equated driving rate of T M is ∼ 9.2 K/T, one time higher than that of Ni 45 Co 5 Mn 36.6 In 13.4 reported in Ref. [47].…”

Section: Magnetocaloric Effect and Magnetoresistance In Codoped Metammentioning

confidence: 63%

“…Usually, the saturated magnetization of low-temperature martensite is higher than that of high-temperature austenite by 10-20%. [44,45] For the present sample, due to the possibility of two-phase coexistence, two abrupt decreases of magnetization take place with increasing temperature. The combined result makes the saturated magnetization of the martensitic state at low temperature 297 K 45% higher than that of the austenitic state at high temperature 310 K for single crystal Ni [12] 037505-3…”

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 79%

“…The huge FM shape memory effect recently discovered in metamagnetic alloys with exact compositions Ni 45 Co 5 Mn 50−x In x (x = 13.3, 13.4, 13.5) [47,48] warrants further experimental and theoretical study. The introduction of Co atoms in metamagnetic alloys enhances the Zeeman energy µ 0 ∆M · H through enlarging the magnetization difference across the martensitic transformation; thus an extremely large stress can be generated by a magnetic field.…”

Section: Magnetocaloric Effect and Magnetoresistance In Codoped Metammentioning

confidence: 95%

“…[13] Later, many scientists devoted their attention to the MCE involving metamagnetic behavior in the alloys. [14][15][16][29][30][31][32][33]53,54,[56][57][58][59][60][61][62][63][64][65][66][67][68] A large inverse ∆S was reported in a number of compositions with rich Mn concentration, such as Ni 45.4 Mn 41.5 In 13.1 , [30] Ni 50−x Mn 39+x Sn 11 , [32] Ni 43 Mn 46 Sn 11 B x , [57] Ni 50 Mn 50−x Sb x , [58] Ni 51 Mn 49−x In x H δ , [59] and Ni 45 (Co 1−x Fe x ) 5 Mn 36.6 In 13.4.…”

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 99%

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Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Hu¹,

Shen²,

Sun³

2013

Chinese Phys. B

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Our recent progress on magnetic entropy change (∆S) involving martensitic transition in both conventional and metamagnetic NiMn-based Heusler alloys is reviewed. For the conventional alloys, where both martensite and austenite exhibit ferromagnetic (FM) behavior but show different magnetic anisotropies, a positive ∆S as large as 4.1 J·kg −1 ·K −1 under a field change of 0-0.9 T was first observed at martensitic transition temperature T M ∼ 197 K. Through adjusting the Ni:Mn:Ga ratio to affect valence electron concentration e/a, T M was successfully tuned to room temperature, and a large negative ∆S was observed in a single crystal. The −∆S attained 18.0 J·kg −1 ·K −1 under a field change of 0-5 T. We also focused on the metamagnetic alloys that show mechanisms different from the conventional ones. It was found that post-annealing in suitable conditions or introducing interstitial H atoms can shift the T M across a wide temperature range while retaining the strong metamagnetic behavior, and hence, retaining large magnetocaloric effect (MCE) and magnetoresistance (MR). The melt-spun technique can disorder atoms and make the ribbons display a B2 structure, but the metamagnetic behavior, as well as the MCE, becomes weak due to the enhanced saturated magnetization of martensites. We also studied the effect of Fe/Co co-doping in Ni 45 (Co 1−x Fe x ) 5 Mn 36.6 In 13.4 metamagnetic alloys. Introduction of Fe atoms can assist the conversion of the Mn-Mn coupling from antiferromagnetic to ferromagnetic, thus maintaining the strong metamagnetic behavior and large MCE and MR. Furthermore, a small thermal hysteresis but significant magnetic hysteresis was observed around T M in Ni 51 Mn 49−x In x metamagnetic systems, which must be related to different nucleation mechanisms of structural transition under different external perturbations.

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Section: Magnetocaloric Effect and Magnetoresistance In Codoped Metammentioning

confidence: 63%

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 79%

Section: Magnetocaloric Effect and Magnetoresistance In Codoped Metammentioning

confidence: 95%

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 99%

See 2 more Smart Citations

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Hu¹,

Shen²,

Sun³

2013

Chinese Phys. B

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“…It is also known that alloys with low T M undergo a weak first order transformation to a micromodulated pre-martensitic phase at ∼ 260K upon cooling [9]. It has been well-established from earlier studies [10] that in Ni 2+x Mn 1−x Ga, increasing Ni content raises the martensitic transformation temperature and lowers the ferromagnetic transformation temperature until they coincide at x = 0.19.…”

Section: Introductionmentioning

confidence: 97%

Composition and temperature dependence of the thermoelectric power of Ni_2+xMn_1−xGa alloys

Bhobe

Monteiro

Cascalheira

et al. 2006

J. Phys.: Condens. Matter

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Abstract. The thermoelectric power (TEP) measurements have been carried out to investigate the changes in the electronic structure associated with the intermartensitic and martensitic transitions in Ni 2+x Mn 1−x Ga (0 ≤ x ≤ 0.19). The samples have been characterized by a.c. magnetic susceptibility measurements. The correlation between the TEP and the microstructural changes sensitive to the increasing Ni content in Ni 2+x Mn 1−x Ga has been investigated. The changes in the density of states as reflected in the temperature variation of the TEP are consistent with the conclusions drawn from the Jahn-Teller mechanism of lattice distortion.

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Shape‐Memory Alloys, Magnetically Activated Ferromagnetic Shape‐Memory Materials

O’Handley¹,

Allen²

2002

Encyclopedia of Smart Materials

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For years it was speculated that the large strains associated with the thermoelastic shape‐memory effect, such as in NiTi alloys, could be captured by application of a magnetic field in certain martensites that are also ferromagnetic. Ferromagnetic shape‐memory alloys (FSMAs) moved from a hypothetical new class of active materials, to join piezoelectric and magnetostrictive materials, upon observation of a 0.2% magnetic field induced strain in a single crystal of Ni 2 MnGa in 1996. This article focuses on the application of a magnetic field to a twinned M phase that is ferromagnetic. It is necessary that the magnetic anisotropy of the M phase be large compared to the energy required for twin boundary motion and, further, that the preferred direction of magnetization changes across the twin boundary. When this is the case, application of a magnetic field results in a difference in Zeeman energy, across the twin boundary. This energy difference exerts a pressure on the twin boundary so as to grow the twin variants having the more favorably oriented magnetization. The resulting field‐induced twin‐boundary motion produces a large strain, fully within the martensitic state of an FSMA. This article describes the crystallography and magnetism of Ni–Mn–Ga in order to explain the very large strains produced by field‐induced twin‐boundary motion in martensite. Examples of field‐induced strain by twin boundary motion in Ni–Mn–Ga FSMA samples having different twin structures are given. Martensitic Fe 70 Pd 30 has also shown field‐induced strains of 0.5%, and efforts are under way to develop other iron‐base FSMAs. These other materials are not be covered in depth. The state of theoretical modeling of strain and magnetization in FSMAs is reviewed. FSMA field‐induced strains are compared and contrasted with the thermoelastic shape‐memory effect and magnetostriction.

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Structural and magnetic phase transitions in shape-memory alloysNi2+xMn1−x

Cited by 424 publications

References 17 publications

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Composition and temperature dependence of the thermoelectric power of Ni_2+xMn_1−xGa alloys

Shape‐Memory Alloys, Magnetically Activated Ferromagnetic Shape‐Memory Materials

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Structural and magnetic phase transitions in shape-memory alloysNi2+xMn1−x

Cited by 424 publications

References 17 publications

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Composition and temperature dependence of the thermoelectric power of Ni2+xMn1−xGa alloys

Shape‐Memory Alloys, Magnetically Activated Ferromagnetic Shape‐Memory Materials

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Product

Resources

About

Composition and temperature dependence of the thermoelectric power of Ni_2+xMn_1−xGa alloys