Transverse dynamical magnetic susceptibilities from regular static density functional theory: Evaluation of damping and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>g</mml:mi></mml:math>shifts of spin excitations

Lounis, Samir; Dias, Manuel dos Santos; Schweflinghaus, Benedikt

doi:10.1103/physrevb.91.104420

Cited by 40 publications

(69 citation statements)

References 66 publications

(70 reference statements)

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“…It was shown that α int scales with the density of states (DOS) at the Fermi energy n(E F ) in the bcc phase [40], and the DOS also exhibits a sharp minimum for Co 25 Fe 75 . This scaling is expected [63,64] if the damping is dominated by the breathing Fermi surface process. With the breathing surface model, the intraband scattering that leads to damping directly scales with n(E F ).…”

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confidence: 66%

Magnetic properties in ultrathin 3d transition-metal binary alloys. II. Experimental verification of quantitative theories of damping and spin pumping

et al. 2017

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General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. A systematic experimental study of Gilbert damping is performed via ferromagnetic resonance for the disordered crystalline binary 3d transition-metal alloys Ni-Co, Ni-Fe, and Co-Fe over the full range of alloy compositions. After accounting for inhomogeneous linewidth broadening, the damping shows clear evidence of both interfacial damping enhancement (by spin pumping) and radiative damping. We quantify these two extrinsic contributions and thereby determine the intrinsic damping. The comparison of the intrinsic damping to multiple theoretical calculations yields good qualitative and quantitative agreement in most cases. Furthermore, the values of the damping obtained in this study are in good agreement with a wide range of published experimental and theoretical values. Additionally, we find a compositional dependence of the spin mixing conductance.

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confidence: 66%

Magnetic properties in ultrathin 3d transition-metal binary alloys. II. Experimental verification of quantitative theories of damping and spin pumping

et al. 2017

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“…Finally, the in-gap states provide a relatively high density of states at the Fermi energy which may profoundly alter the magnetic properties of the system, for instance: the magnetic anisotropy energy [49,50], the response of the impurities to external time-dependent perturbations [51][52][53], their magnetic stability against spin fluctuations [54], and many other phenomena. These properties are currently under investigation.…”

Section: Discussionmentioning

confidence: 99%

Ab initio investigation of impurity-induced in-gap states in Bi2Te3 and Bi2Se3

et al. 2018

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We investigate in-gap states emerging when a single 3d transition metal impurity is embedded in topological insulators (Bi 2 Te 3 and Bi 2 Se 3 ). We use a combined approach relying on first-principles calculations and an Anderson impurity model. By computing the local density of states of Cr, Mn, Fe, and Co embedded not only in surfaces of Bi 2 Te 3 and of Bi 2 Se 3 but also in their bulk phases, we demonstrate that in-gap states originate from the hybridization of the electronic states of the impurity with bulk bands and not with the topological surface states as is usually assumed. This finding is analyzed using a simplified Anderson impurity model. These observations are in contradiction with the prevailing models used to investigate the magnetic doping of topological insulators [R. R. Biswas et al., Phys. Rev. B 81, 233405 (2010)], which attribute the origin of the in-gap states to the hybridization with the topological surface states.

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“…Ebert et al 1 and Lounis et al 28 suggested that α int is proportional to n(E F ) in the breathing Fermi-surface model (that is, intraband transitions) in the cases of a minimally varying spin-orbit coupling (SOC) (as is the case for the Co x Fe 1−x system) and small electron-phonon coupling 2,29 . Alternatively, interband transitions become significant only if bands have a finite overlap due to band broadening, caused for example by coupling to the phonons.…”

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Ultra-low magnetic damping of a metallic ferromagnet

et al. 2016

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Magnetic damping is of critical importance for devices that seek to exploit the electronic spin degree of freedom, as damping strongly a ects the energy required and speed at which a device can operate. However, theory has struggled to quantitatively predict the damping, even in common ferromagnetic materials 1-3 . This presents a challenge for a broad range of applications in spintronics 4 and spin-orbitronics that depend on materials and structures with ultra-low damping 5,6 . It is believed that achieving ultra-low damping in metallic ferromagnets is limited by the scattering of magnons by the conduction electrons. However, we report on a binary alloy of cobalt and iron that overcomes this obstacle and exhibits a damping parameter approaching 10 −4 , which is comparable to values reported only for ferrimagnetic insulators 7,8 . We explain this phenomenon by a unique feature of the band structure in this system: the density of states exhibits a sharp minimum at the Fermi level at the same alloy concentration at which the minimum in the magnetic damping is found. This discovery provides both a significant fundamental understanding of damping mechanisms and a test of the theoretical predictions proposed by Mankovsky and colleagues 3 .In recent decades, several theoretical approaches have attempted to quantitatively predict magnetic damping in metallic systems. One of the early promising theories was that of Kambersky, who introduced the so-called breathing Fermi-surface model 9-11 . More recently, Gilmore and Stiles 2 as well as Thonig et al. 12 demonstrated a generalized torque correlation model that includes both intraband (conductivity-like) and interband (resistivity-like) transitions. The use of scattering theory to describe damping was later applied by Brataas et al. 13 and Liu et al. 14 to describe damping in transition metals. A numerical realization of a linear response damping model was implemented by Mankovsky 3 for Ni-Co, Ni-Fe, Fe-V and Co-Fe alloys. For the Co-Fe alloy, these calculations predict a minimum intrinsic damping of α int ≈ 0.0005 at a Co-concentration of 10% to 20%, but was not experimentally observed 15 .Underlying this theoretical work is the goal of achieving new systems with ultra-low damping that are required in many magnonic and spin-orbitronics applications 7,8 . Ferrimagnetic insulators such as yttrium-iron-garnet (YIG) have long been the workhorse for these investigations, because YIG films as thin as 25 nm have experimental damping parameters as low as 0.9 × 10 −4 (ref. 16). Such ultra-low damping can be achieved in insulating ferrimagnets in part due to the absence of conduction electrons-and, therefore, the suppression of magnon-electron scattering. However, insulators cannot be used in most spintronic and spin-orbitronic applications, where a charge current through the magnetic material is required, nor is the requirement of growth on gadolinium gallium garnet templates compatible with spintronics and complementary metal-oxide semiconductor (CMOS) fabrication processes. One...

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Transverse dynamical magnetic susceptibilities from regular static density functional theory: Evaluation of damping andgshifts of spin excitations

Cited by 40 publications

References 66 publications

Magnetic properties in ultrathin 3d transition-metal binary alloys. II. Experimental verification of quantitative theories of damping and spin pumping

Magnetic properties in ultrathin 3d transition-metal binary alloys. II. Experimental verification of quantitative theories of damping and spin pumping

Ab initio investigation of impurity-induced in-gap states in Bi2Te3 and Bi2Se3

Ultra-low magnetic damping of a metallic ferromagnet

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