Interfacial spin-flip-generated charge pumping

Abstract

Precessing magnetization is known to generate and inject pure spin currents to adjacent materials by the spin pumping effect. However, the generation of the pure spin current is the only case of the spin pumping at the spin-conserving interface. The charge current is usually accompanied by the usual spin pumping effect at the spin-nonconserving interface in general. In this paper, we consider systems where spin can be scattered and flipped by the Elliott-Yafet-like process at interfaces. For these systems, we investigate the interface-generated charge pumping by using the adiabatic quantum pumping theory. We present the analytic expressions for this pumped charge current in terms of the generalized mixing conductances. For the system that we consider, we find interestingly that the connection between the spin pumping effects and magnetoelectronic circuit theory, which has been demonstrated for the spin-conserving systems, can be extended in spin-nonconserving interfaces, and we show that the pumped charge current generated from the interfacial spin-flip potential can be understood in the context of the generalized spin conductance tensors suggested from the generalized magnetoelectronic circuit theory. We also compare the pumped charge current with other mechanisms that generate a charge current or electric voltage in the presence of the precessing magnetization.