Theoretical Study on Gilbert Damping of Nonuniform Magnetization Precession in Ferromagnetic Metals

Umetsu, Nobuyuki; Miura, Daisuke; Sakuma, Atsushi

doi:10.1143/jpsj.81.114716

Cited by 20 publications

(19 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…NB: in the LLG equation, the fluctuation amplitude (that is the width of the Gaussian distribution of the random magnetic field [2]) reads α · k B T /γ m; hence, the response at a temperature T is stronger at the surface than in the bulk. The dependence of α on the layer index is non-monotonous and exhibits oscillations; this finding is at variance with results reported in [54] but agrees with those in [23,24]. The oscillations can be explained by the density of states of the d states which 'carry' the magnetic moment of Co.…”

Section: Damping Tensor At Surfacessupporting

confidence: 86%

See 1 more Smart Citation

Gilbert damping tensor within the breathing Fermi surface model: anisotropy and non-locality

Thonig

Henk

2014

New J. Phys.

View full text Add to dashboard Cite

In magnetization dynamics, the Gilbert damping α is often taken as a parameter. We report on a theoretical investigation of α, taking into account crystal symmetries, spin-orbit coupling and thermal reservoirs. The tensor α is calculated within the Kamberský breathing Fermi-surface model. The computations are performed within a tight-binding electronic structure approach for the bulk and semi-infinite systems. Slater-Koster parameters are obtained by fitting the electronic structure to first-principles results obtained within the multiple-scattering theory. We address the damping tensor for the bulk and surfaces of the transition metals Fe and Co. The role of various contributions are investigated: intra-and interband transitions, electron and magnetic temperature as well as surface orientation. Our results reveal a complicated non-local, anisotropic damping that depends on all three thermal reservoirs.

show abstract

Section: Damping Tensor At Surfacessupporting

confidence: 86%

“…The calculated Gilbert damping is used in an atomistic formulation of the LLG equation [2,3,41]. The temporal evolution of the magnetic moment m i at site i reads [23,24]…”

Section: Theoretical and Computational Aspectsmentioning

confidence: 99%

Gilbert damping tensor within the breathing Fermi surface model: anisotropy and non-locality

Thonig

Henk

2014

New J. Phys.

View full text Add to dashboard Cite

show abstract

“…The last term on the right hand side of Eq. (8) represents other contributions to the torque given as…”

Section: Theoretical Modelmentioning

confidence: 99%

“…The dynamics of magnetization is well described by the extended Landau-Lifshiftz-Gilbert equation given by ∂ t m = −γm × H eff + α 0 m × ∂ t m + T dp , (18) T dp is the dissipative contribution to the torque given in Eq. (8). Again, we consider a onedimensional Walker domain wall parametrized by the domain wall centre X c = X c (t) and tilt angle φ = φ(t).…”

Section: Magnetization Damping From the Scattering Theorymentioning

confidence: 99%

Theory of chiral effects in magnetic textures with spin-orbit coupling

et al. 2018

View full text Add to dashboard Cite

We present a theoretical study of two-dimensional spatially and temporally varying magnetic textures in the presence of spin-orbit coupling (SOC) of both the Rashba and Dresselhaus types. We show that the effective gauge field due to these SOCs, contributes to the dissipative and reactive spin torques in exactly the same way as in electromagnetism. Our calculations reveal that Rashba (Dresselhaus) SOC induces a chiral dissipation in interfacial (bulk) inversion asymmetric magnetic materials. Furthermore, we show that in addition to chiral dissipation αc, these SOCs also produce a chiral renormalization of the gyromagnetic ratioγc, and show that the latter is intrinsically linked to the former via a simple relation αc = (τ /τex)γc, where τex and τ are the exchange time and the electron relaxation time, respectively. Finally, we propose a theoretical scheme based on the Scattering theory to calculate and investigate the properties of damping in chiral magnets. Our findings should in principle provide a guide for material engineering of effects related to chiral dynamics in magnetic textures with SOC.

show abstract

“…The first term is equal to (16)), the approximate result near 0  q is given by (17) indicates that the coefficient of the 2 q term, C, consists of both non-magnetic and magnetic impurity potentials, which was predicted by Umetsu et al 20) Terkovnyak et al 21) have also shown this behavior by only taking into account the non-magnetic impurities. However, note that in the limit of …”

Section: 2mentioning

confidence: 90%

Microscopic Theory of Gilbert Damping for Transition Metal Systems

Sakuma

2013

J. Magn. Soc. Jpn.

Self Cite

View full text Add to dashboard Cite

We provide an overview on the microscopic theory of Gilbert damping and a theoretical framework to calculate the damping constant. In general, the damping constant can be expressed using the spin susceptibility of electronic system using the molecular field Hamiltonian. For a uniform magnetic dynamics (Kittel mode), magnetic damping does not occur unless the magnetic scatterings or spin-orbit interactions exist. Based on these concepts, we have performed the first principles calculation for the Gilbert damping constants  of transition metal systems such as Fe-Ni and Fe-Pt using the tight-binding linear muffin-tin orbital (TB-LMTO) method with inclusion of spin-orbit interactions. Quantitatively, the calculated  's are approximately half of the experimental values, whereas the variations in the Fermi level dependence of  are much larger than these discrepancies． As expected, we confirm that for (Fe-Ni)1 -XPtX and FePt systems the Pt atoms enhance  due to their large spin-orbit coupling. For the disordered alloys, we find that  decreases with an increasing chemical degree of order in the wide range.

show abstract

Theoretical Study on Gilbert Damping of Nonuniform Magnetization Precession in Ferromagnetic Metals

Cited by 20 publications

References 17 publications

Gilbert damping tensor within the breathing Fermi surface model: anisotropy and non-locality

Gilbert damping tensor within the breathing Fermi surface model: anisotropy and non-locality

Theory of chiral effects in magnetic textures with spin-orbit coupling

Microscopic Theory of Gilbert Damping for Transition Metal Systems

Contact Info

Product

Resources

About