Non-quasiparticle effects in half-metallic ferromagnets

Irkhin, V. Yu.; Katsnelson, M. I.; Lichtenstein, A. I.

doi:10.1088/0953-8984/19/31/315201

Cited by 27 publications

(20 citation statements)

References 97 publications

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“…35 taking into account dynamical correlations in Co 2 MnSi results in the emergence of the non-quasiparticle states (NQS's) inside the minorityspin gap, which at finite temperature tend to decrease the spin polarisation at the Fermi level. These NQS's were first predicted theoretically for model systems 64 and stem from the electron-magnon interactions, which are accounted in DMFT (for review, see Ref.…”

Section: Electronic Structurementioning

confidence: 99%

First-principles studies of the Gilbert damping and exchange interactions for half-metallic Heuslers alloys

et al. 2016

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Heusler alloys have been intensively studied due to the wide variety of properties that they exhibit. One of these properties is of particular interest for technological applications, i.e. the fact that some Heusler alloys are half-metallic. In the following, a systematic study of the magnetic properties of three different Heusler families Co2MnZ, Co2FeZ and Mn2VZ with Z = (Al, Si, Ga, Ge) is performed. A key aspect is the determination of the Gilbert damping from first principles calculations, with special focus on the role played by different approximations, the effect that substitutional disorder and temperature effects. Heisenberg exchange interactions and critical temperature for the alloys are also calculated as well as magnon dispersion relations for representative systems, the ferromagnetic Co2FeSi and the ferrimagnetic Mn2VAl. Correlations effects beyond standard density-functional theory are treated using both the local spin density approximation including the Hubbard U and the local spin density approximation plus dynamical mean field theory approximation, which allows to determine if dynamical self-energy corrections can remedy some of the inconsistencies which were previously reported for these alloys.

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Section: Electronic Structurementioning

confidence: 99%

First-principles studies of the Gilbert damping and exchange interactions for half-metallic Heuslers alloys

et al. 2016

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“…Most prominently, the so-called nonquasiparticle states have been invoked. 6,18 However, high-energy photoemission experiments, applied to verify spin integrated calculated valence band densities of states could not confirm the predicted changes in the peak positions. 19,20 Other intrinsic bulk depolarization mechanisms such as spin-orbit interaction, 21 magnetic sublattice noncollinearity, fluctuation-induced hybridization changes, and weakened exchange coupling of the magnetic surface layer have been discussed, 22,23 but still lack experimental verification.…”

Section: Introductionmentioning

confidence: 95%

Surface spin polarization of the nonstoichiometric Heusler alloy Co2MnSi

et al. 2012

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Using a combined approach of spin-resolved photoemission spectroscopy, band structure and photoemission calculations we investigate the influence of bulk defects and surface states on the spin polarization of nonstoichiometric Co 2 Mn α Si thin films (with α = 0.69 and α = 1.19) with bulk L2 1 order. We find that for Mn-poor alloys the spin polarization at the Fermi energy (E F ) is negative due to the presence of Co Mn antisite and minority surface state contributions. In Mn-rich alloys, the suppression of Co Mn antisites leads to a positive spin polarization at E F , and the influence of minority surface states on the photoelectron spin polarization is reduced.

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“…In general, the experimental evidence in favor of halfmetallic behavior is not conclusive [76,159,[183][184][185][186][187]. Among the many reasons for less than 100% polarization are correlation effects [188][189][190][191][192], magnons [147,[183][184][185][186][187]193,194], and irreversible interface compositional changes. Half-metallicity also quickly deteriorates with temperature as the importance of these factors increases.…”

Section: Half-metallic Interfacesmentioning

confidence: 99%

Interface effects in spin-polarized metal/insulator layered structures

Velev

Dowben

Tsymbal

et al. 2008

Surface Science Reports

113

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Recent advances in thin-film deposition techniques, such as molecular beam epitaxy and pulsed laser deposition, have allowed for the manufacture of heterostructures with nearly atomically abrupt interfaces. Although the bulk properties of the individual heterostructure components may be well-known, often the heterostructures exhibit novel and sometimes unexpected properties due to interface effects. At heterostructure interfaces, lattice structure, stoichiometry, interface electronic structure (bonding, interface states, etc.), and symmetry all conspire to produce behavior different from the bulk constituents. This review discusses why knowledge of the electronic structure and composition at the interfaces is pivotal to the understanding of the properties of heterostructures, particularly the (spin polarized) electronic transport in (magnetic) tunnel junctions.

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Non-quasiparticle effects in half-metallic ferromagnets

Cited by 27 publications

References 97 publications

First-principles studies of the Gilbert damping and exchange interactions for half-metallic Heuslers alloys

First-principles studies of the Gilbert damping and exchange interactions for half-metallic Heuslers alloys

Surface spin polarization of the nonstoichiometric Heusler alloy Co2MnSi

Interface effects in spin-polarized metal/insulator layered structures

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