Formation and coupling of magnetic moments in Heusler alloys

Kübler, J.; William, A. R.; Sommers, C.

doi:10.1103/physrevb.28.1745

Cited by 902 publications

(585 citation statements)

References 30 publications

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“…[77][78][79] On the theoretical side, in 1984, Kübler et al gave a detailed account of the formation of local moments in various Mn-based full-Heusler alloys using first-principles calculations. 46 Since then, many authors have studied various semi-and full-Heusler compounds and came to a similar conclusion. An interesting feature arising from the calculations of Heusler alloys is the resemblance of a number of physical characteristics such as the position and the width of the Mn 3d peaks, exchange splitting, and the value of the Mn magnetic moment to the corresponding quantities for diluted Mn impurities in nonmagnetic metals.…”

Section: B Magnetic Moments and Local Moment Behaviormentioning

confidence: 85%

“…46 By analyzing the Mn 3d density of states for different magnetic configurations, the authors proposed the mechanism of an indirect exchange coupling between Mn moments. Recently, the studies of the interatomic exchange interactions and Curie temperatures in Heusler compounds were reported by the present authors [47][48][49][50] and Kurtulus et al 51 …”

Section: Introductionmentioning

confidence: 99%

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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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Section: B Magnetic Moments and Local Moment Behaviormentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

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

2008

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“…They crystallize in the L2 1 structure which is similar to the C1 b structure but now also the vacant site is occupied by a X atom. They have attracted a lot of attention due to the diverse magnetic phenomena they present [6,26] and mainly the transition from a ferromagnetic phase to an antiferromagnetic one by changing the concentration of the carriers [27]. Webster [28] was the first to synthesise full-Heusler alloys containing Co, and Ishida and collaborators [29] have proposed that the compounds of the type Co 2 MnZ, where Z stands for Si and Ge, are also half-ferromagnets.…”

Section: Introductionmentioning

confidence: 99%

Surface properties of the half-and full-Heusler alloys

Galanakis

2002

J. Phys.: Condens. Matter

227

166

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Abstract. Using a full-potential ab-initio technique I study the electronic and magnetic properties of the (001) surfaces of the half-Heusler alloys, NiMnSb, CoMnSb and PtMnSb and of the full-Heusler alloys Co 2 MnGe, Co 2 MnSi and Co 2 CrAl. The MnSb terminated surfaces of the half-Heusler compounds present properties similar to the bulk compounds and, although the half-metallicity is lost, an important spinpolarisation at the Fermi level. In contrast to this the Ni terminated surface shows an almost zero net spin-polarisation. While the bulk Co 2 MnGe and Co 2 MnSi are almost half-ferromagnetic, their surfaces lose the half-metallic character and the net spin-polarisation at the Fermi level is close to zero. Contrary to these compounds the CrAl terminated (001) surface of Co 2 CrAl shows a spin polarisation of about 84%.

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“…In most of the full Heusler alloys, A 2 BC, B is the primary moment carrying atom, in many of the Heusler alloys, A 2 BC, there is presence of a delocalized-like common d-band formed by the d-electrons of the A and B atoms, which are both typically first-row transition metal atoms. 20 Additionally, there is also an indirect RKKYtype exchange mechanism 21 between the B atoms, primarily mediated by the electrons of the C atoms, which also plays an important role in defining the magnetic properties of these materials. 20,22 Staunton et al 23 reported the role of RKKY interaction behind the origin of magnetic anisotropy of a system.…”

Section: Introductionmentioning

confidence: 99%

“…20 Additionally, there is also an indirect RKKYtype exchange mechanism 21 between the B atoms, primarily mediated by the electrons of the C atoms, which also plays an important role in defining the magnetic properties of these materials. 20,22 Staunton et al 23 reported the role of RKKY interaction behind the origin of magnetic anisotropy of a system. For the magnetic shape memory alloys, magnetic anisotropy energy plays an important role.…”

Section: Introductionmentioning

confidence: 99%

Ab initio study of effect of Co substitution on the magnetic properties of Ni and Pt-based Heusler alloys

Roy

Chakrabarti

2017

Physics Letters A

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Using density functional theory based calculations, we have carried out in-depth studies of effect of Co substitution on the magnetic properties of Ni and Pt-based shape memory alloys. We show the systematic variation of the total magnetic moment, as a function of Co doping. A detailed analysis of evolution of Heisenberg exchange coupling parameters as a function of Co doping has been presented here. The strength of RKKY type of exchange interaction is found to decay with the increase of Co doping.

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Formation and coupling of magnetic moments in Heusler alloys

Cited by 902 publications

References 30 publications

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

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

Surface properties of the half-and full-Heusler alloys

Ab initio study of effect of Co substitution on the magnetic properties of Ni and Pt-based Heusler alloys

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