Hyperfine fields and magnetic interactions in Heusler alloys

Khoï, Le Dang; Veillet, P.; Campbell, I. A.

doi:10.1088/0305-4608/8/8/021

Cited by 68 publications

(25 citation statements)

References 28 publications

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“…͑3͒ will be used throughout the further analysis, it should be mentioned that it is a very simple model and a complete description should also include the change of the local magnetic moments and hyperfine fields with the alteration of the environment. 10 Lines with higher resonance frequencies, corresponding to higher hyperfine fields, are assigned to the Fe rich environments of the 55 Mn nuclei, in agreement with the results of the complete substitutional series. The small difference between the magnetic moments of Mn and Fe explains why H 0 ͑Mn͒ stays nearly constant and why the spacing between adjacent lines stays constant, too.…”

Section: ͑3͒supporting

confidence: 84%

“…These probabilities can be directly compared to the intensities of a spin echo NMR measurement, 10 while the corresponding resonance frequencies are related to the hyperfine fields of the active atom in this certain environment as explained in the following.…”

Section: 2mentioning

confidence: 99%

“…10,11 Although Eq. ͑3͒ will be used throughout the further analysis, it should be mentioned that it is a very simple model and a complete description should also include the change of the local magnetic moments and hyperfine fields with the alteration of the environment.…”

Section: ͑3͒mentioning

confidence: 99%

See 2 more Smart Citations

Probing the random distribution of half-metallic Co2Mn1−xFexSi Heusler alloys

Wurmehl

Swagten

Koopmans

et al. 2007

Applied Physics Letters

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Section: ͑3͒supporting

confidence: 84%

Section: 2mentioning

confidence: 99%

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Probing the random distribution of half-metallic Co2Mn1−xFexSi Heusler alloys

Wurmehl

Swagten

Koopmans

et al. 2007

Applied Physics Letters

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“…6 as a function of the Mn-Mn distance R, where J i means the ith neighbor exchange interaction parameter between the Mn atoms in the Mn sublattice. Khoi et al studied the hyperfine fields and magnetic interactions in off-stoichiometric Ni 2 MnSn using NMR spin echo method [24]. They estimated the nearest neighbor exchange interaction parameter J 1 between the Mn atoms on the Sn sites and the Mn sites using molecular field approximation.…”

Section: Resultsmentioning

confidence: 99%

Magnetic properties of Mn-rich Ni2MnSn Heusler alloys under pressure

Chieda

Kanomata

Fukushima

et al. 2009

Journal of Alloys and Compounds

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“…The strength of the transferred hyperfine fields correlates with the amplitude of the s conduction electron spin polarization. Indeed, the measurements by Campbell 94 and Khoi et al 95 showed that maximal s electron spin polarization is found in the systems with high Curie temperatures such as Cu 2 MnAl and Cu 2 MnIn. However, the hyperfine fields are sensitive to only the s electron spin polarization and do not give information about the polarization of the p electrons that are usually dominating in Heusler alloys.…”

Section: Conduction Electron Spin Polarizationmentioning

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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Hyperfine fields and magnetic interactions in Heusler alloys

Cited by 68 publications

References 28 publications

Probing the random distribution of half-metallic Co2Mn1−xFexSi Heusler alloys

Probing the random distribution of half-metallic Co2Mn1−xFexSi Heusler alloys

Magnetic properties of Mn-rich Ni2MnSn Heusler alloys under pressure

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

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