Disordered magnetic multilayers: Electron transport within the coherent potential approximation

Carva, Karel; Turek, I.; Kudrnovský, J.; Bengone, O.

doi:10.1103/physrevb.73.144421

Cited by 105 publications

(119 citation statements)

References 54 publications

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“…39 and the construction of the vertex corrections for transport properties was described in Appendix to Ref. 30.…”

Section: B Effective Torques In the Lmto Methodsmentioning

confidence: 99%

“…Since the necessary formulas of the CPA in multiorbital techniques 30,44 are little transparent, partly owing to the complicated indices of two-particle quantities, we employ here a formalism with the lattice-site index R kept but with all orbital indices suppressed.…”

Section: Auxiliary Quantities and Relationsmentioning

confidence: 99%

“…We show that a similar nonlocal effective torque appears in the fully relativistic linear muffin-tin orbital (LMTO) method in the atomic-sphere approximation (ASA) used recently for calculations of the conductivity tensor in spin-polarized random alloys. 27,28 Here we discuss theoretical aspects of the averaging in the coherent-potential approximation (CPA) 29,30 and illustrate the developed ab initio scheme by applications to selected binary alloys. We also compare the obtained results with those of the LMTO-supercell technique 17 and with other CPA-based techniques, the fully relativistic Korringa-Kohn-Rostoker (KKR) method 19,22 and the LMTO method with a simplified treatment of the SO interaction.…”

Section: Introductionmentioning

confidence: 99%

“…This supplement contains a proof of the equivalence of β loc and β nl and, consequently, of α loc and α nl . The CPA-average in β nl with a nonlocal nonrandom torque has been done using the theory by Velický 29 as worked out in detail within the present LMTO formalism by Carva et al 30 whereas the averaging in β loc involving a local but random torque has been treated using the approach by Butler. 44 …”

Section: Introductory Remarksmentioning

confidence: 99%

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Nonlocal torque operators inab initiotheory of the Gilbert damping in random ferromagnetic alloys

2015

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We present an ab initio theory of the Gilbert damping in substitutionally disordered ferromagnetic alloys. The theory rests on introduced nonlocal torques which replace traditional local torque operators in the well-known torque-correlation formula and which can be formulated within the atomic-sphere approximation. The formalism is sketched in a simple tight-binding model and worked out in detail in the relativistic tight-binding linear muffin-tin orbital (TB-LMTO) method and the coherent potential approximation (CPA). The resulting nonlocal torques are represented by nonrandom, non-site-diagonal and spin-independent matrices, which simplifies the configuration averaging. The CPA-vertex corrections play a crucial role for the internal consistency of the theory and for its exact equivalence to other first-principles approaches based on the random local torques. This equivalence is also illustrated by the calculated Gilbert damping parameters for binary NiFe and FeCo random alloys, for pure iron with a model atomic-level disorder, and for stoichiometric FePt alloys with a varying degree of L10 atomic long-range order.

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“…39 and the construction of the vertex corrections for transport properties was described in Appendix to Ref. 30.…”

Section: B Effective Torques In the Lmto Methodsmentioning

confidence: 99%

Section: Auxiliary Quantities and Relationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductory Remarksmentioning

confidence: 99%

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Nonlocal torque operators inab initiotheory of the Gilbert damping in random ferromagnetic alloys

2015

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“…S β , g β (ϵ ± F ) are the structure constant and the retarded and advanced anxiously Green's function in the most localized β representation of the TB-LMTO-CPA method [8]. Note that the vertex correction is evaluated by means of the ladder approximation to satisfy the charge conservation law [10]. The lattice constants are set to a experimental data, a = 5.755Å for Co 2 MnAl, a = 5.655Å for Co …”

Section: Methodsmentioning

confidence: 99%

First-principles study for electronic structure and physical property of Co-based Heusler alloys

Kota

Sakuma

2011

J. Phys.: Conf. Ser.

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Abstract.The statistical investigation of the physical property of Co-based Heusler alloys with the atomic composition or configuration dependence are carried out in first-principles approach. In particular, the electronic structure, magnetic moment and electrical resistivity due to disorder alloy effects of Co2MnAl1−zSiz (0.0 < z < 1.0) and Co2Mn1−yFeySi (0.0 < y < 1.0) with the L21, B2 and A2 structure are calculated by using the tight-binding linear muffin-tin orbital method combined with the coherent potential approximation based on the local spindensity functional approximation and by using the Kubo-Greenwood formula, respectively. The obtained results indicate that these properties of the Co-based Heusler alloys significantly depend on the atomic configuration and composition, especially, they are sensitive to the existence of the half-metallic property.

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Spin‐mixing conductances: The influence of disorder

Carva

Turek

2008

Physica Status Solidi (a)

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1 Introduction and theory If a current incident on a thin ferromagnetic (FM) layer is polarized noncollinearly with respect to the layer magnetization, it exerts a spin-transfer torque on the magnetic layer and may change its magnetization direction [1]. This phenomenon attracts ongoing interest because of its high application potential. Spin-transfer torque exerted on a magnetic layer can be viewed as a linear response to the spin accumulation inside an adjacent non-magnetic layer. The complex spin-mixing conductance [2] provides -together with the usual spin-resolved conductances in current-perpendicularto-plane (CPP) geometry -complete information on a linear response of particle and spin currents due to the bias and spin accumulation in the adjacent metals.Here we use the recently introduced ab initio materialspecific approach to this observable [3] based on nonequilibrium Green's functions formalism. The numerical implementation employs the local spin density approximation (LSDA) and the tight-binding linear muffin-tin orbital (TB-LMTO) method [4]. The spin-mixing conductance

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Disordered magnetic multilayers: Electron transport within the coherent potential approximation

Cited by 105 publications

References 54 publications

Nonlocal torque operators inab initiotheory of the Gilbert damping in random ferromagnetic alloys

Nonlocal torque operators inab initiotheory of the Gilbert damping in random ferromagnetic alloys

First-principles study for electronic structure and physical property of Co-based Heusler alloys

Spin‐mixing conductances: The influence of disorder

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