Magnetocrystalline anisotropy and Gilbert damping in iron-rich Fe1−xSixthin films

Abstract

The magnetocrystalline anisotropy of Fe 1−x Si x (0 x 0.4) epitaxial thin films on MgO(001) was studied by ferromagnetic resonance. The experimental results are in good agreement with theoretical predictions of ab initio electronic structure calculations using the fully relativistic Korringa-Kohn-Rostoker Green's function method within spin-density-functional theory. The Gilbert damping α is found to be isotropic by theory and experiment with a minimum at the composition x = 0.2.

Magnetic anisotropy, damping, and interfacial spin transport in Pt/LSMO bilayers

“…The best fit gives the Gilbert constant α LSMO = 1.9(1) × 10 −3 . This value is low among reported values of LSMO films on STO(001) 21,36 and is comparable to the lowest values reported for metallic ferromagnetic films: α = 2.1 × 10 −3 in epitaxial Fe-V alloy, 37 2.3 × 10 −3 in epitaxial Fe 1−x Si x , 38 …”

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

“…23 The ab initio studies have also been successful in reproduction and interpretation of values and concentration trends of the Gilbert damping in random ferromagnetic alloys, such as the NiFe alloy with the face-centered cubic (fcc) structure (Permalloy) 17,22 and Fe-based alloys with the body-centered cubic (bcc) structure (FeCo, FeV, FeSi). 19,22,24 Other studies addressed also the effects of doping the Permalloy and bcc iron by 5d transitionmetal elements 19,20,22 and of the degree of atomic longrange order in equiconcentration FeNi and FePt alloys with the L1 0 -type structures. 20 Recently, an application to halfmetallic Co-based Heusler alloys has appeared as well.…”

“…25 The obtained results revealed correlations of the damping parameter with the density of states at the Fermi energy and with the size of magnetic moments. 22,24 In a one-particle mean-field-like description of a ferromagnet, the total spin is not conserved due to the XC field and the SO interaction. The currently employed forms of the torque operators T µ in the torque-correlation formula (2) reflect these two sources; both the XC-and the SO-induced torques are local and their equivalence for the theory of Gilbert damping has been discussed by several authors.…”

Magnetic Anisotropy in the (Cr0.5Mn0.5)2GaC MAX Phase

“…[22,26,27] Considering that there is no significant magnetocrystalline anisotropy in the film plane as indicated by the lack of an in-plane FMR angular dependence in the epitaxial film, we calculate the resonance frequency using the effective uniaxial anisotropy field given by the shape anisotropy (1/2)μ 0 (N ⊥ − N )M 2 eff for thin films, where M eff is the effective magnetization. Note that M eff (from FMR) and magnetization, M , measured by SQUID magnetometry can differ and such variations can be attributed to an out-of-plane anisotropy along the c axis.…”

“…The resonance frequency can then be calculated analytically using the double derivatives of the magnetic free energy F with respect to polar and azimuthal angles [22,26,27]:…”