Diffraction induced Spin Pumping in Normal-Metal/Multiferroic-Helimagnet/Ferromagnet Heterostructures

TL;DR

This paper investigates how spin and charge currents are generated through diffraction effects in a heterostructure involving a multiferroic helimagnet, revealing gauge dependence unique to dynamic pumping phenomena.

Contribution

It introduces the concept of diffraction-induced spin pumping in heterostructures with multiferroic helimagnets, highlighting the role of diffracted states and gauge dependence in the pumping process.

Findings

Spin and charge flow driven by magnetization precession is governed by diffracted states.

Gauge dependence in pumped current is observed, unlike in static transport.

Diffraction effects significantly influence spin pumping in the studied heterostructures.

Abstract

Generally the adiabatic quantum pumping phenomenon can be interpreted by the surface integral of the Berry curvature inside the cyclic loop. Spin angular momentum flow without charge current can be pumped out by magnetization precession in ferromagnet-based structures. When an electron is scattered by a helimagnet, spin-dependent diffraction occurs due to the spatial modulation of the spiral. In this work, we consider the charge and spin flow driven by magnetization precession in normal-metal/multiferroic-helimagnet/ferromagnet heterostructures. The pumping behavior is governed by the diffracted states. Gauge dependence in the pumped current was encountered, which does not occur in the static transport properties or pumping behaviors in other systems.