First-principles calculations of spin spirals in<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:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">MnGa</mml:mi></mml:math>and<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:mr

Enkovaara, Jussi; Ayuela, Andrés; Jalkanen, Jari; Nordström, Lars; Nieminen, Risto M.

doi:10.1103/physrevb.67.054417

Cited by 73 publications

(53 citation statements)

References 34 publications

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“…The magnetic measurements have shown that addition of Fe or Co instead of Ni results in increase of Curie temperature T C . This observation together with the theoretical suggestion 25) gives a basic ground for the development of high temperature ferromagnetic shape memory alloys in the Ni-Mn-Ga system.…”

Section: Resultsmentioning

confidence: 99%

“…The experimentally observed increase of T C in Ni 2:16Àx Co x Mn 0:84 Ga and Ni 2:20Àz Fe z Mn 0:80 Ga is in accordance with a recent theoretical consideration of magnetic properties of Ni 2 MnGa and Ni 2 MnAl. 25) In Ref. 25) a suggestion was made that Ni significantly affects T C in these alloys and, therefore, Curie temperature in Ni 2 MnGa could be increased by a substitution of the Ni sites.…”

Section: Nominal Compositionmentioning

confidence: 99%

“…25) In Ref. 25) a suggestion was made that Ni significantly affects T C in these alloys and, therefore, Curie temperature in Ni 2 MnGa could be increased by a substitution of the Ni sites. Note also that this suggestion is in accordance with empirical observation that Curie temperature of Co 2 MnZ or Cu 2 MnZ (Z is a nontransition element) alloys is higher than T C in corresponding Ni 2 MnZ alloys.…”

Section: Nominal Compositionmentioning

confidence: 99%

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Influence of Fe and Co on Phase Transitions in Ni-Mn-Ga Alloys

et al. 2003

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Differential scanning calorimetry (DSC) and magnetic measurements were performed to study the influence of ferromagnetic 3-d transition elements Fe and Co on structural and magnetic properties of ferromagnetic shape memory alloys Ni 2 MnGa. Addition of Fe or Co on the Ni sites decreases the temperature of martensitic phase transition T m , whereas addition of Co on the Mn sites results in a considerable increase of T m . Magnetic measurement revealed that Curie temperature T C increases upon substitution of Fe or Co for Ni. This observation is of importance for design of high temperature ferromagnetic shape memory alloys.

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Section: Resultsmentioning

confidence: 99%

Section: Nominal Compositionmentioning

confidence: 99%

Section: Nominal Compositionmentioning

confidence: 99%

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Influence of Fe and Co on Phase Transitions in Ni-Mn-Ga Alloys

et al. 2003

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“…18 The mixed B2 / L2 1 of Ni 2 MnAl has been used to produce negative magnetoresistance ratio in granular films. 19 First-principles calculations by Enkovaara et al on Ni 2 MnAl have confirmed the FM character of the L2 1 structure, 20 while Büsgen and collaborators have shown that the Ni 50 Mn x Al 50−x is FM from 14 to 31 at. % of Mn.…”

mentioning

confidence: 99%

Structural-induced antiferromagnetism in Mn-based full Heusler alloys: The case of Ni2MnAl

Galanakis

Şaşıoğlu

2011

Appl. Phys. Lett.

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“…20,21 In MSM alloys, an external magnetic field can induce large strains when applied in the martensitic state. 22 The MSM alloys are of great interest as promising smart materials for future technological applications. 20,[23][24][25] They can be used as sensors and actuators in different fields of applications.…”

Section: Introductionmentioning

confidence: 99%

Role of conduction electrons in mediating exchange interactions in Mn-based Heusler alloys

2008

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Because of the large spatial separation of the Mn atoms in Heusler alloys ͑d Mn-Mn Ͼ 4 Å͒, the Mn 3d states belonging to different atoms do not overlap considerably. Therefore, an indirect exchange interaction between Mn atoms should play a crucial role in the ferromagnetism of the systems. To study the nature of the ferromagnetism of various Mn-based semi-and full-Heusler alloys, we perform a systematic first-principles calculation of the exchange interactions in these materials. The calculation of the exchange parameters is based on the frozen-magnon approach. The Curie temperature is estimated within the mean-field approximation. The calculations show that the magnetism of the Mn-based Heusler alloys depends strongly on the number of conduction sp electrons, their spin polarization, and the position of the unoccupied Mn 3d states with respect to the Fermi level. Various magnetic phases are obtained depending on the combination of these characteristics. The magnetic phase diagram is determined at zero temperature. The results of the calculations are in good agreement with available experimental data. Anderson's s-d model is used to perform a qualitative analysis of the obtained results. The conditions leading to a diverse magnetic behavior are identified. If the spin polarization of the conduction electrons at the Fermi energy is large and the unoccupied Mn 3d states lie well above the Fermi level, a Ruderman-Kittel-Kasuya-Yoshida-type ferromagnetic interaction is dominating. On the other hand, the contribution of the antiferromagnetic superexchange becomes important if unoccupied Mn 3d states lie close to the Fermi energy. The resulting magnetic behavior depends on the competition of these two exchange mechanisms. The calculation results are in good correlation with the conclusions made on the basis of the Anderson s-d model which provides useful framework for the analysis of the results of first-principles calculations and helps to formulate the conditions for high Curie temperature.

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First-principles calculations of spin spirals inNi2MnGaandNi2

Cited by 73 publications

References 34 publications

Influence of Fe and Co on Phase Transitions in Ni-Mn-Ga Alloys

Influence of Fe and Co on Phase Transitions in Ni-Mn-Ga Alloys

Structural-induced antiferromagnetism in Mn-based full Heusler alloys: The case of Ni2MnAl

Role of conduction electrons in mediating exchange interactions in Mn-based Heusler alloys

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