Spin-density fluctuations and the fluctuation-dissipation theorem in 3d ferromagnetic metals

Abstract

Spatial and time scales of spin density fluctuations (SDF) were analyzed in 3d ferromagnets using ab initio linear response calculations of complete wavevector and energy dependence of the dynamic spin susceptibility tensor. We demonstrate that SDF are spread continuously over the entire Brillouin zone and while majority of them reside within the 3d bandwidth, a significant amount comes from much higher energies. A validity of the adiabatic approximation in spin dynamics is discussed. The SDF spectrum is shown to have two main constituents: a minor low-energy spin wave contribution and a much larger high-energy component from more localized excitations. Using the fluctuation-dissipation theorem (FDT), the on-site spin correlator (SC) and the related effective fluctuating moment were properly evaluated and their universal dependence on the 3d band population is further discussed.

References in corpus (16)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Metallic Quantum Ferromagnets
• Linear Response Calculations of Spin Fluctuations
• Electronic structure of Pu and Am metals by self consistent relativistic GW
• Wannier-function approach to spin excitations in solids
• Different dimensionality trends in the Landau damping of magnons in iron, cobalt and nickel: time dependent density functional study
• Spin wave dispersion based on the quasiparticle self-consistent $GW$ method: NiO, MnO and $\alpha$-MnAs
• Theory of Local Dynamical Magnetic Susceptibilities from the Korringa-Kohn-Rostoker Green Function Method
• Transverse dynamical magnetic susceptibilities from regular static density functional theory: Evaluation of damping and g-shifts of spin-excitations
• Magnetic exchange in $\alpha$-iron from the ab initio calculations in the paramagnetic phase
• Self-consistent Green function approach for calculations of electronic structure in transition metals
• Zero-point spin-fluctuations of single adatoms
• Effects of Spin Fluctuations and Anomalous Thermal Expansion of delta-Plutonium
• Strength and scales of itinerant spin fluctuations in 3d paramagnetic metals

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