Temperature Dependent Ferromagnetic Resonance via the Landau-Lifshitz-Bloch Equation: Application to FePt

Abstract

Using the Landau-Lifshitz-Bloch (LLB) equation for ferromagnetic materials, we derive analytic expressions for temperature dependent absorption spectra as probed by ferromagnetic resonance (FMR). By analysing the resulting expressions, we can predict the variation of the resonance frequency and damping with temperature and coupling to the thermal bath. We base our calculations on the technologically relevant L1${}_0$ FePt, parameterised from atomistic spin dynamics simulations, with the Hamiltonian mapped from ab-initio parameters. By constructing a multi-macrospin model based on the LLB equation and exploiting GPU acceleration we extend the study to investigate the effects on the damping and resonance frequency in $\mu$m sized structures.

arXiv comment10 pages, 8 figures

References in corpus (8)

• Atomistic spin model simulations of magnetic nanomaterials
• Fokker-Planck and Landau-Lifshitz-Bloch Equations for Classical Ferromagnets
• Temperature dependent magnetic properties of FePt: effective spin Hamiltonian model
• Dynamic approach for micromagnetics close to the Curie temperature
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• Magnetic anisotropy of FePt: effect of lattice distortion and chemical disorder
• Suppression of spin-torque in current perpendicular to the plane spin-valves by addition of Dy cap layers

Cited by in corpus (4)

• Model of damping and anisotropy at elevated temperatures: application to granular FePt films
• Roles of heating and helicity in ultrafast all-optical magnetization switching in TbFeCo
• Size-dependent frequency bands in the ferromagnetic resonance of a Fe-nanocube
• Stratonovich-Ito integration scheme in ultrafast spin caloritronics