Spin pumping by a field-driven domain wall

Abstract

We present the theory of spin pumping by a field-driven domain wall for the situation that spin is not fully conserved. We calculate the pumped current in a metallic ferromagnet to first order in the time derivative of the magnetization direction. Irrespective of the microscopic details, the result can be expressed in terms of the conductivities of the majority and minority electrons and the dissipative spin transfer torque parameter ␤. The general expression is evaluated for the specific case of a field-driven domain wall and for that case depends strongly on the ratio of ␤ and the Gilbert damping constant. These results may provide an experimental method to determine this ratio, which plays a crucial role for current-driven domain-wall motion.

Spin torques due to diffusive spin current in magnetic texture

“…As a reciprocal to the current-induced spin torque, a spin motive force is known to be generated by the dynamics of magnetization texture [24][25][26][27][28][29] , and actually has been detected experimentally 30 . In this context, two of the present authors studied microscopically the spin and charge transport induced by magnetization dynamics 31 .…”

“…In this context, two of the present authors studied microscopically the spin and charge transport induced by magnetization dynamics 31 . They obtained a 'local' charge current, j (L) = σ s E s , driven by a spin motive force field [24][25][26][27][28][29] …”

Spin-Motive Force Caused by Vortex Gyration in a Circular Nanodisk with Holes

“…Equation (2) describes the ith component of the electric field induced by spin-motive force [5][6][7][8][9][10][11]13]: (2) where A s is the vector potential, V s is the scalar potential, m is the unit vector of magnetization, and ± stands for spin-up and spin-down bands. When we calculate the electric field using Eq.…”

“…A voltage drop occurs in the direction of DW propagation, which depends only on the transformation frequency of the DW. This provides experimental evidence of spin-originated EMF, which is expressed as the cross product of the spatial gradient of magnetization and its time derivative [8][9][10][11][12].…”

Magnetocaloritronic nanomachines

“…The spin-transfer torque [12,13] in spin valves and domain walls [14,15,16] has been well understood for transition-metal based magnets [17,18,19] which already led to many applications [20]. The reciprocal effect to the spin-transfer torque results in electromotive forces induced by the magnetization dynamics [21,22,23,24]. All these pave the way for novel devices that can output as well as be controlled by temperature gradients, electric currents, and magnetic fields.…”