Electrons in a ferromagnetic metal with a domain wall

Abstract

We present theoretical description of conduction electrons interacting with a domain wall in ferromagnetic metals. The description takes into account interaction between electrons. Within the semiclassical approximation we calculate the spin and charge distributions, particularly their modification by the domain wall. In the same approximation we calculate local transport characteristics, including relaxation times and charge and spin conductivities. It is shown that these parameters are significantly modified near the wall and this modification depends on electron-electron interaction.Comment: 10 pages with 4 figure

Current-Induced Spin Accumulation and Spin Transfer Torque in a Néel Domain Wall

“…The rst step of the analysis is to perform a unitary transformation to a local frame, ψ → T (z)ψ with T † (z)T (z) = 1, which removes the inhomogeneity of n(z) [1]. In other words, T (z) transforms the second term in Eq.…”

“…The transformed Hamiltonian in the adiabatic approximation, which is valid for thick domain walls, L ≫ λ (where λ is the electron wavelength), can be written in the basis of semiclassical functions as [1]:…”

“…This contribution is generally positive (domain wall increases the resistance), but surprisingly in some situations (especially for rather thick domain walls) contribution to the resistance from a domain wall may be negative. This is generated by spin accumulation in the domain wall [1]. Thus, spin accumulation created in equilibrium situation (zero current) is important for resistance of the system.…”

“…Hence, in this paper we calculate the current-induced (nonequilibrium) spin accumulation in a model ferromagnetic system with a relatively thick Néel domain wall. The approach is based on some unitary transformation, that has been used earlier to calculate the domain wall resistance [1]. The current-induced spin density is then calculated using linear response theory and the Green function formalism.…”

“…Thus, spin accumulation created in equilibrium situation (zero current) is important for resistance of the system. This spin accumulation is oriented along the local magnetization associated with a domain wall [1].…”