Exchange interaction function for spin-lattice coupling in bcc iron

Abstract

Functional representations of the spin polarization and the exchange interaction in terms of the lattice configuration is necessary to model the dynamics of the coupled spin and lattice subsystems in large-scale atomistic simulation of magnetic materials. Data needed for this purpose have only existed in the regime of small displacements from the equilibrium perfect lattice configurations. In this paper, we report and discuss the results of our first-principles calculations for bcc iron over a wide range of lattice constants using the magnetic force theorem and the one-electron Green's function. Despite the relatively complex functional form of the exchange interaction function for bcc iron our results show that it can be expressed as a superposition of Bethe-Slater-type curves representing interatomic exchange interaction of the 3d electrons.

Grain boundary anisotropy on nano-polycrystalline magnetic thin films

“…Election is based in our interest of considering variations in ion distance. Such election for J exc is supported by several DFT studies in metals where curve of J exc vs. distance between magnetic ion presents similar tendencies 12,13 . The length of the Fermi wave vector, k F , was set to 1, which is a typical value for metals 11 .…”

Engineering perpendicular magnetic anisotropy in Fe via interstitial nitrogenation: N choose K

“…It has been well established by experiment 5,8 and theory [14][15][16][17] that the increase of the total magnetic moment in strained α-Fe can be understood as a straight-forward magneto-volume effect. But more than that for α ′ -Fe 8 N x thin films experimentally also a switching of the magnetization from in-plane direction to out-of-plane (perpendicular) direction along the crystallographic c-axis has been observed, 7,8 but remained elusive to theoretical understanding.…”

Modelling of Spin-Dependent Mechanical Friction at Atomic Level

“…The values of L-J potential parameters and have been estimated considering the nearest neighbors distance and cohesive energy corresponding to real Fe monocrystal of bcc structure [10]. Recent spin-polarized electronic structure calculations predict the value of the effective exchange integral for bcc iron greater than 0.01 eV [11]. Moreover, it has been assumed, that "decay constant" is equal to the distance for bcc iron.…”